Managing private use of program execution capacity

ABSTRACT

Techniques are described for managing execution of programs, including using excess program execution capacity of one or more computing systems. For example, a private pool of excess computing capacity may be maintained for a user based on unused dedicated program execution capacity allocated for that user, with the private pool of excess capacity being available for priority use by that user. Such private excess capacity pools may further in some embodiments be provided in addition to a general, non-private excess computing capacity pool that is available for use by multiple users, optionally including users who are associated with the private excess capacity pools. In some such situations, excess computing capacity may be made available to execute programs on a temporary basis, such that the programs executing using the excess capacity may be terminated at any time if other preferred use for the excess capacity arises.

BACKGROUND

Many companies and other organizations operate computer networks thatinterconnect numerous computing systems to support their operations,such as with the computing systems being co-located (e.g., as part of alocal network) or instead located in multiple distinct geographicallocations (e.g., connected via one or more private or publicintermediate networks). For example, data centers housing significantnumbers of interconnected computing systems have become commonplace,such as private data centers that are operated by and on behalf of asingle organization, and public data centers that are operated byentities as businesses to provide computing resources to customers. Somepublic data center operators provide network access, power, and secureinstallation facilities for hardware owned by various customers, whileother public data center operators provide “full service” facilitiesthat also include hardware resources made available for use by theircustomers. However, as the scale and scope of typical data centers hasincreased, the task of provisioning, administering, and managing thephysical computing resources has become increasingly complicated.

The advent of virtualization technologies for commodity hardware hasprovided some benefits with respect to managing large-scale computingresources for many customers with diverse needs, allowing variouscomputing resources to be efficiently and securely shared by multiplecustomers. For example, virtualization technologies such as thoseprovided by VMWare, XEN, Linux's KVM (“Kernel-based Virtual Machine”),or User-Mode Linux may allow a single physical computing machine to beshared among multiple users by providing each user with one or morevirtual machines hosted by the single physical computing machine, witheach such virtual machine being a software simulation acting as adistinct logical computing system that provides users with the illusionthat they are the sole operators and administrators of a given hardwarecomputing resource, while also providing application isolation andsecurity among the various virtual machines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are network diagrams illustrating example embodiments ofinteractions to manage use of program execution capacity available tomultiple users of a program execution service.

FIGS. 2A and 2B illustrate examples of techniques for managing use ofprogram execution capacity of multiple computing nodes.

FIG. 3 is a block diagram illustrating an example embodiment of acomputing system for managing use of computing nodes by multiple users.

FIG. 4 illustrates a flow diagram of an example embodiment of a Program

Execution Service System Manager routine.

FIGS. 5A and 5B illustrate a flow diagram of an example embodiment of anExcess Capacity Usage Manager routine.

FIG. 6 illustrates a flow diagram of an example embodiment of a

Dedicated Capacity Usage Manager routine.

FIG. 7 illustrates a flow diagram of an example embodiment of anOn-Demand Variable Capacity Usage Manager routine.

DETAILED DESCRIPTION

Techniques are described for managing execution of programs. In at leastsome embodiments, the execution of programs is managed for multipleusers using excess computing capacity of one or more computing systems.In particular, in at least some such embodiments, for each of one ormore users, a private pool of excess computing capacity is maintainedfor and associated with that user, such as based on currently unusedprogram execution capacity that has been allocated for dedicated use bythat associated user, and with the private pool of excess computingcapacity being available for priority use by the associated user. Suchprivate excess computing capacity pools may further in some embodimentsbe provided in addition to a general, non-private excess computingcapacity pool that is available for use by multiple users, optionallyincluding the one or more users who are associated with the privateexcess computing capacity pool(s). The techniques may in someembodiments be used in conjunction with a program execution service(“PES”) that executes multiple programs on behalf of multiple customersor other users of the service, such as a program execution service thatprovides multiple computing nodes (e.g., multiple physical computingsystems and/or virtual machines that are hosted on one or more physicalcomputing systems) for executing user programs. In addition, in at leastsome embodiments, some or all of the techniques may be automaticallyperformed by embodiments of a Program Execution Service System Managermodule, as described in greater detail below.

In some embodiments, at least some excess or otherwise unused programexecution capacity of a PES or other group of computing nodes may bemade available to execute programs on behalf of users on a temporary ornon-guaranteed basis, such that the excess program execution capacitymay be available to execute such programs until a time that the programexecution capacity is desired for other purposes (e.g., for preferentialor reserved use to execute one or more other programs). Such excessprogram execution capacity may, for example, be made available as partof one or more general excess computing capacity pools that areavailable for use by various users (e.g., any customers of a PES thatprovides the general excess computing capacity pools), such as via aspot market with dynamically changing pricing to reflect supply anddemand, or instead in other manners. In some cases, one or more programsmay be executing on behalf of a user using excess program executioncapacity at the time that the excess program execution capacity isdesired for other purposes, and, in some such cases, the execution ofthose one or more programs may be automatically terminated (e.g., shutdown, aborted, etc.) by the PES in order to make that excess programexecution capacity available for the other purposes. In at least somesuch embodiments, programs that are automatically terminated may beautomatically restarted on behalf of the user at a future time, such asa future time when a sufficient amount of excess program executioncapacity again becomes available to execute the programs for the user.Alternatively, rather than terminating the one or more programs that areusing excess program execution capacity that is desired for otherpurposes, in some embodiments and situations, other program executioncapacity may be identified and used in place of the excess programexecution capacity that is desired for the other purposes, so as toenable the one or more programs using the excess program executioncapacity to continue to execute. Additional details related to usingexcess program execution capacity are included below.

In some embodiments, at least some of the program execution capacityavailable from a PES for executing programs may be allocated to one ormore users for preferential use by those users, such that each of thoseusers has priority access relative to other users to use a respectiveamount of the program execution capacity. For example, the priorityaccess of the users may be based on each of the users having dedicatedor exclusive access to use the respective amount of program executioncapacity (e.g., each user having one or more dedicated computing nodesand/or portions thereof that are allocated for reserved or guaranteeduse by the user in executing programs, or each user instead having anamount of program execution capacity that is equivalent to one or morecomputing nodes that is dedicated to the user to be available from alarger group of multiple computing nodes used by multiple users). In atleast some such embodiments, a respective amount of program executioncapacity of a PES may be allocated to a particular user for dedicatedaccess over a specified period of time, such as in a manner analogous toa lease of one or more physical computing systems so that the respectiveamount of program execution capacity may be available for executingprograms on behalf of the user throughout the specified period of time.In addition, in some embodiments, a user may be given preferential orother dedicated access to execute programs based on one or more factors,such as fees paid by the user, an agreement to a contractual obligationfor using the dedicated access for a period of time and/or subject toother conditions, etc.

In at least some embodiments, at least some of the program executioncapacity that is allocated to one or more users for dedicated or otherpreferential use may be used as excess program execution capacity duringsome times, such as when the allocated dedicated capacity is not beingused for a preferential use and/or when the user to whom the dedicatedcapacity is allocated makes the allocated dedicated capacity availablefor use as excess capacity. In this manner, at least some programexecution capacity that is allocated to a first group of users maybecome available from time to time to temporarily execute programs onbehalf of other users. When the demand for excess program executioncapacity from multiple users is greater than the currently availablesupply, particular users and programs may be selected to use the excessprogram execution capacity in various ways. For example, in someembodiments, a user who requests excess program execution capacity toexecute a program may be given priority over other such users based onone or more factors, such as fees offered and/or paid by the user, atime that a request to use the excess program execution capacity issubmitted, a time at which or by which excess program execution capacityuse is requested to start, an amount of time or a deadline by whichexcess program execution capacity use is requested to be completed, atype and/or amount of excess program execution capacity requested (e.g.,a specified quantity of computing nodes), etc. Additional detailsrelated to the use of dedicated program execution capacity are includedbelow.

In addition, as previously noted, one or more users may each have anassociated private pool of excess computing capacity for which the userhas exclusive or priority access in at least some embodiments. Forexample, if a user has dedicated computing capacity of one or morecomputing nodes, but is not currently using some or all of thatdedicated capacity, the user may be given priority access to use thatunused dedicated capacity as a private pool of excess computing capacityin executing programs for the user. In some embodiments, such a privatepool of excess computing capacity for a user may be established inresponse to explicit instructions from the user (e.g., for a fee fromthe user), while in other embodiments some or all such users that haveunused dedicated computing capacity may each automatically receive aprivate pool of excess computing capacity based on their unuseddedicated computing capacity. Furthermore, if a user automaticallyreceives a private pool of excess computing capacity using their ownunused dedicated computing capacity, the user may in some embodiments beunaware of the private pool.

The use of such a private pool of excess computing capacity for a usermay provide various benefits to the user in various embodiments andsituations. For example, in some embodiments, the ongoing incrementalcost for a user to make use of their dedicated computing capacity may belower than the cost to the user to make use of a comparable amount ofexcess computing capacity from a general pool—if so, the cost to theuser for using their own private pool of excess computing capacity maybe set at a rate that is less than the cost of the use of the generalpool (e.g., may be the same cost as the ongoing incremental cost for auser to make use of their dedicated computing capacity, may be betweenthe ongoing incremental cost for a user to make use of their dedicatedcomputing capacity and the higher cost of using excess computingcapacity from the general pool, etc.). In addition, in some embodiments,a user may receive exclusive or priority access to the excess computingcapacity in their own private pool, such that the user is able toimmediately execute an excess computing capacity request using theirprivate pool, even if that same request would not have sufficiently highpriority to be immediately executed using a general excess computingcapacity pool. Thus, use of such a private pool of excess computingcapacity for a user to execute a program may provide beneficial programexecution characteristics that differ from at least some other programexecution characteristics occurring from use of a general excesscomputing capacity pool to execute the program, such as one or more oflower incremental cost of use of a specified amount of program executioncapacity for a specified time interval, enhanced availability to obtainaccess to computing capacity from the private pool relative to thegeneral pool, enhanced ability to continue execution of the programusing computing capacity from the private pool relative to the generalpool, etc.

As one specific example of use of a private excess computing capacitypool, a first user may initiate dedicated use of multiple computingnodes for a particular purpose, but maintain a portion of those multiplecomputing nodes in reserve (e.g., to reserve 20% of the total multiplecomputing nodes as backup for possible later use, such as to be able toautomatically scale the computing nodes being used for the particularpurpose in response to higher-than-expected computing load and/or to beable to replace any computing nodes being used for the particularpurpose if they become unavailable)—in such situations, the computingnodes that are in reserve may be used as a first private pool of excesscomputing capacity for the first user while they are not being used forthe particular purpose, but with those computing nodes that are inreserve being available to the first user for the particular purpose ifthey are later desired. As another specific example of use of a privateexcess computing capacity pool, a second user may initiate dedicated useof multiple computing nodes, but with all of the multiple computingnodes intended for use by the second user as a second private pool ofexcess computing capacity for the second user—the second private pool ofexcess computing capacity may then be used to fulfill requests frommultiple entities associated with the second user (e.g., if the seconduser represents an organization, and the multiple entities are differentgroups or people within the organization; with the multiple entitiesbeing third-parties to which the second user sells access to the secondprivate pool of excess computing capacity; etc.), such as in a mannersimilar to the techniques described herein for managing multiplerequests from multiple users to use a general excess computing capacitypool. Furthermore, if the second private pool of excess computingcapacity for the second user is used to fulfill requests from multipleentities, the management of those requests and that second private poolmay in some embodiments be performed by a third-party operator of a PESand/or a Program Execution Service System Manager (“PESSM”) module(e.g., for a fee charged to the second user), while in other embodimentsthe second user may obtain and use a PESSM module or otherwise beenabled to perform such actions on their own behalf. Moreover, in someembodiments, some or all of the dedicated capacity computing nodes thatare used for a user may be provided by or otherwise managed by thatuser, such as, for example, if the first and/or second users noted aboveprovide at least some of the computing nodes used for the first andsecond excess computing capacity pools, respectively.

If a user has a private pool of excess computing capacity and there is aseparate general pool of excess computing capacity that is alsoavailable, the different excess computing capacity pools may be used invarious manners. For example, if such a user makes a request to useexcess computing capacity, the request may first be satisfied using thatuser's private pool if it has sufficient computing capacity for therequest, and otherwise the request may be considered for satisfaction bythe general excess computing capacity pool along with requests fromother users. Similarly, if one or more first programs are being executedfor such a user by using the user's private pool of excess computingcapacity, and that excess computing capacity is desired by the user forother purposes (e.g., to execute one or more other second programs forthe user as part of the user's dedicated computing capacity), theexecution of the one or more first programs may in some embodimentsautomatically be moved to the general excess computing capacity pool(e.g., by continuing execution of the first programs withouttermination, such as by identifying and using other available computingcapacity to serve as a replacement part of the user's dedicatedcomputing capacity; by terminating execution of the first programs onone or more computing nodes that are part of the user's dedicatedcomputing capacity, and initiating further execution of the firstprograms in an immediate or rapid manner using other computing nodesthat are part of the general pool of excess computing capacity; byterminating execution of the first programs on one or more computingnodes that are part of the user's dedicated computing capacity, andplacing a request for further execution of the first programs in arequest queue along with other requests for use of the general excesscomputing capacity pool; etc.). Additional details related to the use ofprivate excess computing capacity pools are included below.

In addition to the types of dedicated and excess computing capacitycapabilities that are discussed above, a PES may further includeon-demand variable program execution capacity that is available tosatisfy at least some dynamically received requests of users to executeprograms (e.g., immediately upon request of those users, at an indicatedfuture time, at some time during an indicated future time period, etc.)in some embodiments, such that the one or more programs indicated bysuch a request may be executed if computing resources sufficient tosatisfy the requested execution are available at (or near) the requestedtime, but without such a request being guaranteed to be satisfied (i.e.,without sufficient computing resources being guaranteed to beavailable). For example, after an on-demand variable program executioncapacity request is received to dynamically execute one or more programson behalf of a user (e.g., for immediate execution), the one or moreprograms may be executed for the user if an appropriate amount ofon-demand program execution capacity is currently available forexecuting those programs (e.g., if it is determined that there is asufficient number of available computing nodes with resources to satisfythe request), and otherwise the request may be denied (or in some cases,postponed). Thus, in some such embodiments, such a request for on-demandvariable program execution capacity may be unsuccessful, such as if theappropriate amount of program execution capacity is not available toexecute the one or more programs at the time of the requested execution(e.g., if it is determined that there are not enough currently availablecomputing nodes with sufficient resources to satisfy a request forimmediate execution).

In some embodiments, the computing nodes used to provide the on-demandvariable program execution capacity may be distinct from the computingnodes used to provide dedicated program execution capacity and/or fromthe computing nodes used to provide excess program executioncapacity—thus, if some of the computing nodes used to provide theon-demand variable program execution capacity are not in use, in someembodiments they may be used to provide excess program executioncapacity until on-demand variable program execution capacity requestsare received, while in other embodiments they may not be used to providesuch excess program execution capacity. In addition, in someembodiments, after an on-demand variable program execution capacityrequest for immediate (or scheduled) execution is satisfied andsuccessfully initiates execution of one or more programs on behalf of arespective user, the ongoing use of the on-demand variable programexecution capacity may be guaranteed to continue until some future time,such as a time of the respective user's choosing (e.g., based on anindication received from the respective user to terminate use of and/orrelease the program execution capacity) and/or a time based upon designby the user (e.g., the one or more programs executing on behalf of theuser automatically terminate the execution, such as upon completion of atask or otherwise; an application and/or other user interacting with theone or more programs executing on behalf of the respective userterminates the execution, such as if the one or more programs executingfor the respective user are provided for interactive use of others;etc.). Alternatively, in some embodiments, the guaranteed ongoing use ofthe variable program execution capacity may be subject to certainlimitations, such as to be guaranteed that the PES will not preempt theuse for other purposes, but not to be guaranteed against failure of thecomputing nodes executing the programs.

In addition, as previously noted, dedicated program execution capacityfunctionality of a PES may be available for one or more users in atleast some embodiments, such that each of the one or more users may havesome dedicated amount of program execution capacity that is allocated bythe PES and guaranteed to be available for executing programs on behalfof the one or more users (e.g., a dedicated number of one or morecomputing nodes provided by the PES, a dedicated portion of thecomputing resources provided by a group of one or more of the computingnodes of the PES, etc.). For example, the guaranteed availability of thededicated program execution capacity may be provided in conjunction withone or more QoS (“Quality Of Service”) criteria, such as that thededicated program execution capacity will be available within aspecified period of time after a request to initiate execution of anindicated program (e.g., a period of time that corresponds toterminating execution of other programs using excess computing capacityand to initiating execution of the indicated program). In contrast tothe on-demand variable program execution capacity functionality and theexcess program execution capacity functionality, a user of dedicatedcapacity functionality may have some specified amount of programexecution capacity that is guaranteed to be available for executingprograms on behalf of the user during a specified use period, barringunforeseen and/or occasional events rendering services of the PESunavailable (e.g., service failure, maintenance, etc).

Furthermore, in embodiments in which a PES provides two or more ofdedicated computing capacity, excess computing capacity and on-demandvariable computing capacity to users for fees, the fees associated withthe different types of computing capacity may differ in various manners,such as to reflect associated availability guarantees and/or otherfactors. As one example, the overall cost for a user to make use of aparticular amount of dedicated computing capacity may be higher than thecost to the user to make use of a comparable amount of on-demandvariable computing capacity (if available), and that cost to the user touse the on-demand variable computing capacity may be higher than thecost to the user to make use of a comparable amount of excess computingcapacity (if available) from a general pool—in some cases, however, thecost of using dedicated computing capacity may include a one-time orperiodic fee that is not based on actual use, and a separate ongoingincremental cost for a user to make use of a particular amount ofdedicated computing capacity for a particular amount of time, with thatongoing incremental cost for a particular amount of dedicated computingcapacity use optionally being less than the cost for using a comparableamount of general excess computing capacity pool for that period oftime. Furthermore, as noted above, costs for using a private excesscomputing capacity pool may differ from those of using a general excesscomputing capacity pool, such as to in some embodiments be the same asthe ongoing incremental cost for dedicated computing capacity use.Additional details related to pricing and costs are included below.

FIG. 1A is a network diagram that illustrates an example of managing useof multiple types of program execution capacity to execute programs formultiple users. For illustrative purposes, some examples and embodimentsare described below in which specific types of program executioncapability are provided and managed in specific manners. These examplesare provided for illustrative purposes and are simplified for the sakeof brevity, and it will be appreciated that the inventive techniques maybe used in a wide variety of other situations, only some of which aredescribed below.

In the example of FIG. 1A, a number of users are interacting over anetwork 100 with an illustrated embodiment of a Program ExecutionService System Manager module 110 to execute programs on one or morecomputing nodes 120 available for executing programs of the users, withthe PESSM module 110 providing some or all of the functionality of aparticular program execution service (not shown). In particular, in theillustrated embodiment, the PESSM module 110 and the computing nodes 120are provided by a program execution service provider 105 as part of aprovided program execution service, and the PESSM module 110 may executeon one or more computing systems (not shown). In this example, theprogram execution service provides a variety of functionality formanaging execution of programs on the computing nodes 120 for varioususers.

Various remote users 130, 140, 150 and 160 may interact over the network100 with the PESSM 110 in this example to configure and/or requestvarious types of execution of programs on behalf of the users. In thisexample, the remote users include one or more dedicated capacity users140, one or more excess capacity users 150, one or more on-demandvariable capacity users 130, and optionally one or more other users 160,as discussed below. The network 100 may, for example, be a publiclyaccessible network of linked networks, possibly operated by variousdistinct parties, such as the Internet. In other embodiments, thenetwork 100 may be a private network, such as, for example, a corporateor university network that is wholly or partially inaccessible tonon-privileged users. In still other embodiments, the network 100 mayinclude one or more private networks with access to and/or from theInternet.

The illustrated computing nodes 120 are provided for use in executingprograms on behalf of the users, and in some embodiments may includemultiple physical computing systems and/or multiple virtual machinesthat are hosted on one or more physical computing systems (as isdescribed in greater detail with respect to FIG. 1B). Each of thecomputing nodes 120 has some amount of computing resources available forexecuting one or more programs and provides a specific amount of programexecution capacity, such as may be measured, for example, by acombination of one or more of processing capacity (e.g., number and/orsize of processing units), memory capacity, storage capacity, networkbandwidth capacity, etc. In some embodiments, the PES provider 105 mayprovide preconfigured computing nodes, with each preconfigured computingnode having similar and/or equivalent amounts of resources available forexecuting programs on behalf of users, while in other embodiments, thePES provider 105 may provide a selection of various different computingnodes from which a user may choose for executing programs on behalf ofthe user, such as each selection having varying amounts and/or types ofcomputing-related resources (e.g., size, speed and/or type of processingunits; number of processing units; amount of memory and/or storage;platform configuration, such as 32-bit or 64-bit; etc.).

In some embodiments, the various users 130, 140, 150 and 160 mayinteract with the PESSM 110 to specify preferred and/or requiredresources for execution of programs on behalf of the users (e.g., byspecifying one or more computing nodes, etc.). In various embodiments,such resources may be specified at the time of a request for executionof programs on behalf of a user and/or at one or more other times, suchas when a user registers and/or subscribes to use services of theprogram execution service. In some embodiments, the PESSM 110 mayprovide subscription and/or registration services to one or more users,such that users may specify information related to one or more programsto execute on behalf of a user (e.g., programs, source code, addressablelocations of one or more programs, etc.), account information (e.g.,user name, billing information, etc.), terms of use, etc. In addition,after a user interacts with the PESSM 110 to subscribe and/or registerfor services, the user may in some embodiments be issued one or moreidentifiers (e.g., keys, tokens, user names, certificates, etc.) thatare associated with the user and are used in conjunction with executingprograms on behalf of the user. In other embodiments, a module otherthan the PESSM 110 may be provided to perform various operations relatedto subscription and/or registration services of a PES.

In the illustrated embodiment, one or more variable capacity users 130are interacting with the PESSM 110 to configure and/or request executionof one or more programs using on-demand variable program executioncapacity, such as by submitting a request for immediate execution and/orproviding information for later execution. After a request for immediateexecution is received, the PESSM 110 may determine whether there are asufficient number of computing nodes 120 with available resources forsatisfying the request, and if so, the PESSM 110 may initiate executionof one or more programs for the request on an appropriate amount of thecomputing nodes on behalf of the user. In cases where a user schedules arequest for one or more future executions of one or more programs, thePESSM 110 may attempt to reserve an appropriate amount of computingnodes for executing the one or more programs at the one or more futuretimes, and/or may delay the determination of which computing nodes touse for execution until a later time (e.g., such as when the one or morefuture times occur). In the illustrated embodiment, if the PESSM 110 isunable to allocate computing nodes for executing a variable capacityuser request, the request may fail, such that the programs are notexecuted. In such cases, the user 130 may resubmit a failed request forlater execution. As previously noted, in some embodiments, a variablecapacity user may be charged various fees in association with use of thePES, such as based on a number of computing nodes used, a type ofcomputing nodes used, a duration of time the computing nodes are used,etc. In addition, while not illustrated here, some portion of thecomputing nodes 120 may in some embodiments be specified to provide theon-demand variable program execution capacity, while in otherembodiments the on-demand variable program execution capacity may beprovided in other manners (e.g., using all of the computing nodes 120;using all of the computing nodes 120 that are not allocated for anotherpurpose, such as for dedicated capacity; etc.).

In addition, in this example, a subset of the computing nodes 120 hasbeen allocated for use by one or more of the dedicated capacity users140, such that each of the one or more dedicated capacity users 140 mayhave priority access to execute programs for the user on at least someportion of those allocated computing nodes. For example, in someembodiments, each of the dedicated capacity users 140 may have one ormore computing nodes 120 dedicated for executing programs of that userduring a specified use time period, such that the user may access theone or more computing nodes at any time during the specified use periodto execute programs on behalf of the user and/or may continuouslyexecute programs on the one or more computing nodes for the duration ofthe specified period. As one specific example, one or more of thededicated capacity users 140 may enter into a long-term (e.g., 1 yearterm) agreement with the PES provider 105, such that each of those usershas priority access to a dedicated amount of the computing nodes 120over the term of the agreement in exchange for a fixed fee payment(e.g., upfront or periodically billed) and, in some cases, other usefees (e.g., variable fees associated with use of various resources, suchas electricity, physical rack space, network utilization, etc.).

After a dedicated capacity user 140 interacts with the PESSM 110 torequest priority use of a dedicated amount of computing nodes, the PESSM110 may allocate one or more computing nodes from the computing nodes120 for dedicated use by the user. For example, in some embodiments, oneor more specific computing nodes of the multiple computing nodes 120(e.g., one or more specific physical computing nodes and/or virtualcomputing nodes) may be allocated for priority use by an associatedspecific dedicated capacity user for an entire use period (e.g., such asby allocating the specific computing nodes at the time of registration,and/or at one or more other times), such that requests to executeprograms on behalf of the specific dedicated user on dedicated computingnodes during the use period results in initiation of execution of theprograms on the specific one or more allocated computing nodes. In otherembodiments, rather than allocate specific computing nodes to specificdedicated users 140 for an entire use period, the PESSM 110 may insteadallocate computing nodes from a dedicated computing node group havingmultiple computing nodes, such that an appropriate amount of computingnodes with sufficient resources to satisfy requests for execution by thevarious dedicated capacity users 140 may be available in the dedicatedcomputing node group. In some such embodiments, after a request isreceived to execute one or more programs for a dedicated user 140 on oneor more dedicated computing nodes, an appropriate amount of computingnodes 120 sufficient to execute the programs may be selected from thededicated computing node group at the time of the request to execute theone or more programs. After the selected amount of computing nodes areno longer used for executing the request for the dedicated user 140(e.g., after termination and/or completion of the requested execution),those computing nodes may be returned to the dedicated computing nodegroup for use by other dedicated capacity users, and in some embodimentsmay further be tracked as being available for use as part of a privatepool of excess computing capacity for that dedicated user 140, asdiscussed below. In addition, after a use period for a particulardedicated capacity user 140 expires, the one or more computing nodesallocated for use by that user may similarly be released for use byothers, such as by, for example, making the computing nodes available tobe allocated for use by one or more other (e.g., new) dedicated capacityusers. In addition, the PESSM 110 may perform one or more various othermanagement operations with respect to fulfilling requests for execution,such as, for example, enforcing use periods and/or other restrictionsassociated with requests and/or users submitting requests, freeing-upcomputing resources to fulfill the requests, authorizing and/orauthenticating the requests and/or the requesting users, etc. In someembodiments, a delay may be incurred between a time that a request forexecution on dedicated program execution capacity and a time that therequest is fulfilled, such as a delay period for performing various ofthe management operations, etc. In various other embodiments, computingnodes for dedicated capacity users may be allocated, tracked, reservedand/or released using various other techniques.

In addition, in the illustrated embodiment, multiple excess capacityusers 150 are interacting with the PESSM 110 to configure and/or requestexecution of one or more programs using excess program executioncapacity of the PES—such excess capacity users may include users who useprivate excess capacity pools and/or one or more general excess capacitypools. As previously noted, excess program execution capacity mayinclude excess and/or unused program execution capacity that may beotherwise allocated for other uses, and in some embodiments may beseparated into at least one general excess capacity pool that includesthe excess computing capacity that is not in use as part of one or moreother private excess capacity pools. For example, in the illustratedembodiment, excess program execution capacity may include a number ofthe computing nodes 120 that are otherwise allocated for other purposes(e.g., for use by dedicated capacity users 140, variable capacity users130, and/or other users 160), but are not currently being used for thosepurposes. The excess capacity users may configure requests for executionof programs in various ways in various embodiments, such as byspecifying a number and/or type of computing nodes for execution ofprograms, a minimum and/or maximum number of computing nodes to use, anexpiration time for the request, a preferred execution time and/orperiod of execution, one or more bids for payment of use of excessprogram execution capacity (e.g., a bid per each use of a computingnode, a bid per use of one or more computing nodes per some unit oftime, a minimum and/or maximum bid, etc), etc.

As is further discussed with respect to FIGS. 2A and 2B, the illustratedembodiment of the PESSM 110 may determine when to include and/or removeone or more computing nodes 120 from excess program execution capacitythat is available for use by excess capacity users 150, when to initiateand/or terminate requested execution of programs for excess capacityusers 150, and on which of the computing nodes 120 available for use byexcess capacity users to execute the programs. In addition, the PESSM110 may further track how much excess capacity is available for each ofone or more excess capacity users 150 in private excess capacity poolsfor those users, such as for some or all excess capacity users 150 thatare also dedicated capacity users 140. In various embodiments, the PESSM110 may determine that one or more computing nodes are unused and/or orotherwise available for use by excess capacity users 150 in variousways. For example, in some embodiments, the PESSM 110 may receiveindications from various users and/or entities that one or morecomputing nodes are not being used or are otherwise available for use byexcess capacity users, such as indications from one or more dedicatedcapacity 140 users that they are not using some number and/or portion ofthe computing nodes dedicated for use by those users. In some suchembodiments, such dedicated capacity users may indicate one or moretimes at which dedicated computing nodes are likely to be or arecommitted by the dedicated capacity users to be unused and/or available(e.g., particular times of day, particular days, periods of time, etc.).In addition, in some embodiments, one or more other users 160 mayinteract in similar manners to indicate that one or more computingnodes, such as one or more computing nodes under the control of the oneor more other users 160 (e.g., third party computing systems, notshown), are available for use by excess capacity users.

In other embodiments, the PESSM 110 may automatically determine whencomputing nodes are available for excess capacity users, such as, forexample, by monitoring some or all computing nodes 120 to determine whenthe computing nodes are not being used and/or by tracking usage patternsof one or more users of such computing nodes (e.g., dedicated capacityusers 140, variable capacity users 130, other users 160, etc.). In somesuch cases, determining whether computing nodes are unused or otherwiseunderutilized may include determining and/or predicting a likelihoodthat the computing nodes will remain unused for at least a period oftime sufficient to execute programs of one or more excess capacityusers, such as, for example, based on an analysis of past use patternsof the computing nodes by one or more users. In various embodiments, aperiod of time sufficient to execute programs of one or more excesscapacity users may be based on one or more considerations, such as atime to stop/start programs on behalf of users, a time to configurecomputing nodes for use, a type of program executed on behalf of anexcess capacity user (e.g., some types of programs may perform usefulamounts of work in short periods of time, such as various types of dataprocessing, etc., while other programs use longer periods of time beforeuseful results are produced), etc.

After it is determined that one or more computing nodes 120 areavailable for use by one or more excess capacity users 150, suchcomputing nodes may be added to a general pool of available excessprogram execution capacity and/or otherwise tracked as being part of oneor more private excess capacity pools, such that the one or morecomputing nodes may be used by the PESSM 110 for executing programs onbehalf of corresponding excess capacity users 150 until such time thatother uses of the computing nodes arise (e.g., such as priority usage bydedicated capacity users 140, variable computing users 130, and/or oneor more other users or entities 160). The PESSM 110 may furtherdetermine that one or more of the excess capacity computing nodes are nolonger available for use by excess capacity users 150 in various ways invarious embodiments. For example, in some embodiments, the PESSM 110 mayreceive indications that one or more computing nodes are no longeravailable, such as based on explicit requests to stop use of thecomputing nodes from a user 160 that controls those computing nodes,requests to execute programs of priority users on the one or morecomputing nodes, an expiration of a specified period of availability,etc. As another example, in some embodiments, the PESSM 110 mayautomatically determine other uses for the computing nodes, such as, forexample, based on received requests from one or more users thatcorrespond to the other uses, or based on determining a likely demandfor one or more computing nodes 120 (e.g., based on detecting anincreased usage of other resources and/or programs for which thecomputing nodes may be used, etc.).

In some embodiments, an excess capacity user 150 may interact with thePESSM 110 to request immediate execution of one or more programs on aspecified number of excess computing nodes and/or to schedule suchexecution at one or more future times, such that the PESSM 110 mayinitiate the requested execution on the specified number of excesscomputing nodes if it is determined that the specified number of excesscomputing nodes are available at the time of the requested execution.The determination of whether the specified number of excess computingnodes are available at the time may include first considering whether aprivate excess capacity pool (if any) for the user includes thespecified number of excess computing nodes, and selecting those excesscomputing nodes for use if they are available. If only a subset of thespecified number of excess computing nodes are available in a privateexcess capacity pool for the user, the PESSM 110 may in some embodimentsselect those private excess computing nodes to use in partiallyfulfilling the request, and attempt to obtain the remaining excesscomputing nodes from the general excess capacity pool, or instead mayproceed in other manners (e.g., fulfilling the request using only thesubset of available private excess computing nodes; indicating that therequest fails because the private excess capacity pool does not includeall of the specified number of excess computing nodes; attempting tofulfill the request using only excess computing nodes from the generalexcess capacity pool; etc.). In addition, in some embodiments, an excesscapacity user 150 may interact with the PESSM 110 to configure a requestfor execution of one or more programs on a specified number of excesscomputing nodes to be performed as such excess computing nodes becomeavailable to execute the one or more programs, such as during anindicated future period of time, and in some such embodiments the PESSM110 may initiate the requested execution on the specified number ofexcess computing nodes when it determines that the specified number ofexcess computing nodes are available during that period of time. In someembodiments, an excess capacity user 150 may specify a minimum and/ormaximum number of excess computing nodes to use for performing arequested execution, such that the requested execution is initiated ifthe PESSM 110 determines that at least the minimum number of excesscomputing nodes are available (whether from a private excess capacitypool and/or a general excess capacity pool), and the PESSM 110 mayinitiate the requested execution on up to the maximum (if specified)number of excess computing nodes for the request based on availabilityof the excess computing nodes.

After a request for execution of one or more programs on behalf of anexcess capacity user 150 is received, if the PESSM 110 determines thatthere are an appropriate number of computing nodes with sufficientcomputing resources to satisfy the requested execution (whether from aprivate excess capacity pool and/or a general excess capacity pool), thePESSM may select which of the available computing nodes to use for therequested execution in various ways. For example, in some embodiments,the PESSM may simply select an appropriate number of excess computingnodes from any of the available computing nodes with sufficientresources, such as, for example, by randomly selecting from a pool ofavailable computing nodes. In other embodiments, one or more specificcomputing nodes may be selected on the basis of one or more otherfactors, such as, for example, a predicted length of and/or likelihoodof continued availability of the one or more specific computing nodes, aphysical proximity of the one or more specific computing nodes to one ormore other computing nodes, a geographic location of the one or morespecific computing nodes and/or one or more other computing nodes, etc.Furthermore, if one or more particular computing nodes have beendedicated for use by a particular user, those particular computing nodesmay be the only ones used as part of a private excess capacity pool forthat particular user.

As previously noted, execution of programs for excess capacity users onexcess computing nodes may be temporary, such that the PESSM 110 mayautomatically terminate such programs when other preferred uses for theexcess computing nodes arise (e.g., such as if the excess computingnodes are reclaimed by a dedicated capacity user 140 who previously wasnot using a decided computing node, etc.). In such cases, if programsare currently executing on behalf of excess capacity users 150 on any ofthose excess computing nodes, then those programs may be automaticallyterminated (e.g., aborted, shut down, hibernated, etc.), such that thecomputing nodes are free for other purposes and no longer available forexcess capacity users. In addition, as discussed in greater detailelsewhere, in some embodiments the execution state of those programs maybe saved before they are terminated, such as to enable a later restartof the program. Furthermore, in some such embodiments, there may bemultiple excess computing nodes currently executing programs on behalfof excess capacity users 150 that may be capable of satisfying thenumber of computing nodes for the other purposes, and in such cases, thePESSM 110 may determine which of the excess computing nodes to free forthe other purposes based on various factors (e.g., by first reclaimingexcess capacity computing nodes from a private excess capacity pool of auser for use in fulfilling a request from that user for dedicatedcapacity use; or by using a determined priority among the currentrequests of the excess capacity users, such as based on time submitted,bid prices, etc.). In some embodiments, at least some of the terminatedprograms may have their execution be migrated and/or reinitiated on oneor more other available excess computing nodes (if any), such asimmediately or at a later time. In some such cases, if there are notenough excess computing nodes available to satisfy all of the currentexcess capacity users 150 who are executing programs (or requestingexecution of programs), then the PESSM 110 may determine to terminateone or more additional programs executing on one or more other excesscomputing nodes such that the one or more programs initially terminatedthat were executing on the specific computing nodes may be reinitiatedon the newly freed excess computing nodes (e.g., based on a determinedpriority of the excess capacity users, such that the requests associatedwith the one or more initially terminated programs that were executingon the specific computing nodes have higher priority than at least someof the requests associated with the one or more additional programs). Insome embodiments, after the PESSM 110 automatically terminates a programof a user, the PESSM 110 may automatically reinitiate the execution ofthe programs as excess computing nodes become available to execute theprograms for the user. In addition, in other embodiments, at least someterminated programs of a user may be automatically migrated and/orreinitiated on one or more other computing systems and/or programexecution services with sufficient computing resources available toexecute the programs, including one or more computing nodes availablevia variable capacity functionality provided to variable capacity users130, dedicated capacity functionality provided to dedicated capacityusers 140, and/or one or more third-party computing systems (not shown)external to the PES.

In addition, various types of programs may be better suited forexecuting in such a temporary execution environment as provided byexcess capacity pools, such as programs that are relatively tolerant ofunexpected interruptions due to occasional termination. In someembodiments, excess capacity users may execute one or more programs onthe excess program execution capacity that are designed tointermittently track and/or save progress (e.g., intermediate results,current runtime state, etc.), so that the programs may be reinitiated ata future time to resume activities. In addition, in some embodiments,when the PESSM 110 automatically terminates programs executing on excesscomputing nodes, the PESSM 110 may automatically detect the currentsystem and/or program execution state, such that the detected state maybe saved and/or provided to a respective excess capacity user 150, sothat later execution of the programs may be resumed in a state similarto when the programs were automatically terminated. Alternatively, if aparticular executing program is able to save its own execution state,the PESSM 110 may instead notify the program to perform its ownexecution state save before terminating the program. Additional detailsrelated to example embodiments of saving program execution state areincluded in U.S. patent application Ser. No. 12/334,004, filed Dec. 12,2008 and entitled “Saving Program Execution State,” which is herebyincorporated by reference in its entirety.

As previously noted, in at least some embodiments, a user having aprivate excess capacity pool receives priority access to any programexecution capacity in that private excess capacity pool (e.g., so as toexecute any excess capacity requests from the user before any excesscapacity requests from any others), but if such a private excesscapacity pool includes excess capacity that is not currently in use bythe associated user for the private pool, that currently availableexcess capacity may be made temporarily available via a general excesscapacity pool to other users. In addition, access to excess computingnodes from a general excess capacity pool for executing programs onbehalf of multiple excess capacity users 150 may be based on priorityamong the excess capacity users 150 in at least some embodiments, suchthat if there is contention for some amount of the excess computingnodes between two or more requests to execute programs, the requesthaving a higher associated priority will be provided access to use thecontended amount of excess computing nodes for executing programs. In atleast one illustrative embodiment, requests with the highest bid amounts(e.g., a highest maximum bid) may be given priority over requests withlower bids, with ties between bid amounts being resolved based on otherfactors (e.g., which request was received earlier). In some embodiments,one or more of the excess capacity users 150 may interact with anembodiment of the PESSM 110 to bid (e.g., auction-style) on access toone or more available excess computing nodes (e.g., currently availableand/or available at one or more future times) of the general excesscapacity pool, such that the user with the winning bid may receive theaccess to the one or more available excess computing nodes. In someembodiments, the PESSM 110 may automatically terminate execution ofprograms associated with lower priority requests that are currentlyexecuting on one or more of the excess computing nodes in favor ofexecuting programs of higher priority requests on the one or more excesscomputing nodes. In some other embodiments, such as non-priority basedembodiments, the PESSM 110 may instead occasionally rotate throughpending requests to execute programs on excess computing nodes, suchthat each request may be provided some amount of execution time on oneor more of the excess computing nodes.

In some embodiments, the PESSM 110 may provide interactive feedback toone or more of the excess capacity users 150 that are interacting withthe PESSM 110 to configure and/or request execution of programs on someamount of excess computing nodes of a general excess capacity pool. Forexample, in some such embodiments, interactive feedback may includeindications of when and/or for how long requested programs may be likelyto execute on the indicated amount of excess computing nodes, such asbased on current and/or predicted demand, current and/or likely amountsof excess computing nodes, one or more bid-levels, etc. In oneillustrative embodiment, the PESSM 110 may indicate suggested bid levelsalong with corresponding information indicating when requested executionwill likely occur and/or complete, such that the excess capacity user150 may reconfigure (e.g., by specifying a different bid, a differentamount and/or type of computing nodes, a different duration ofexecution, etc.) a request to meet the desires of the excess capacityuser, such that the request may be performed at an earlier time, etc.

As previously noted, excess capacity users 150 may be charged variousfees in conjunction with use of excess program execution capacity, suchas based on whether the excess program execution capacity being used fora user is part of a private excess capacity pool for that user, based ona quantity of computing nodes used and/or one or more use factors (e.g.,number of times used, amount of shared resources consumed, amount oftime computing nodes are used, etc.), and/or based on one or more bidsfrom the one or more excess capacity users 150 for use of the computingnodes. In some embodiments, a portion of the fees charged to the one ormore excess capacity users 150 who use a general excess computingcapacity pool may be supplied to one or more other users who providedcomputing nodes in that general excess capacity pool (e.g., one or morededicated capacity users 140, one or more other users 160, etc.). Forexample, in some embodiments, such other users may be paid aproportional share of some amount of the fees that are collected fromexcess capacity users, such as a proportional share reflective of theamount of computing nodes contributed by the other users over time. Insome cases, such fees supplied to the other users may be automaticallycredited and/or paid to the other users by the PES provider, such as tooffset other charges incurred by those other users, such as chargesincurred by dedicated capacity users.

In addition, in some embodiments, the PESSM 110 may provide anelectronic marketplace (not shown) to one or more dedicated capacityusers 140, such that the one or more dedicated capacity users 140 maytransfer access to their dedicated computing nodes to one or more otherusers 160 during the use time period of the dedicated capacity, while inother embodiments a dedicated capacity user 140 and an other user 160may arrange an exchange in a manner external to the PES. In someembodiments, a user 160 may provide payment to a dedicated capacity userin exchange for access to a transferred portion of the dedicatedcapacity user's dedicated computing nodes, such that the purchasing usermay access the transferred portions of dedicated program executioncapacity to execute programs on behalf of the purchasing user. A pricefor the exchanged access may be determined in various manners in variousembodiments, such as via a fixed price specified by the dedicatedcapacity user, a price that is bid or suggested by the user 160, etc. Insome embodiments, an exchange for dedicated computing nodes may be madesuch that the exchange is temporary and/or permanent. For example, insome embodiments, an exchange may be made for a specified limited periodof time and/or various intervals of time, such that the purchasing usermay access the computing nodes during that specified time and/or duringthe various intervals, after which the dedicated computing nodes mayrevert back to the dedicated capacity user for use by the dedicatedcapacity user. In other embodiments, the exchange may be permanent, suchthat the purchasing user may be provided with access to the dedicatedcomputing nodes for any remaining use period associated with thededicated computing nodes. In some embodiments, as part of the initialallocation of one or more computing nodes for dedicated use by asubscribing dedicated capacity user 140, the PESSM 110 may assign one ormore user tokens to the subscribing user and/or may otherwise associatethe allocated computing nodes with the subscribing dedicated capacityuser's account, such that the dedicated capacity user's use of thecomputing nodes may be tracked for various purposes (e.g.,configuration, authorization, billing, etc.)—in such embodiments, when adedicated capacity user transfers a portion of their dedicated computingnodes to a new user, any provided tokens may be transferred to the newuser and/or the portion of computing nodes may be otherwise associatedwith an account of the new user. In some embodiments, a provider of thePESSM 110 may further collect a fee in conjunction with a transfer of aportion of dedicated computing nodes from one user to another.

Although the foregoing example embodiment of FIG. 1A is described withrespect to a PES that provides various types of functionality forvarious types of users, such as variable capacity users, dedicatedcapacity users and excess capacity users, it will be appreciated thatvarious other embodiments may exist, such as embodiments with or withoutone or more of the various types of users.

For example, it will be appreciated that some embodiments may existwhere a program execution service provides functionality for excesscapacity users, but does not include variable and/or dedicated capacityusers, such as where the excess program execution capacity is providedby one or more third-parties and/or affiliate entities associated withthe PES, such as to allow such parties and/or entities to monetizeotherwise unused computing resources. In addition, some of thetechniques may be used in conjunction with a bid-based PES that allowsusers to submit requests for and/or to schedule execution of programs ona temporary basis on all of the program execution capacity provided bythe service, such that requests with higher priority at the time ofexecution are executed. In addition, it will be appreciated that thevarious users 130, 140, 150 and 160 may each act as one or more of theother various users at times, such as when those users are accessingassociated functionality of the types corresponding to those othervarious users, including for dedicated capacity users 140 to at timesact as excess capacity users 150 and use private excess capacity poolsbased on those users' unused dedicated capacity. As another example, insome embodiments, a particular user who acts as a dedicated capacityuser to execute programs on dedicated program execution capacity mayalso act as an on-demand variable capacity user, such as when theparticular user desires additional computing resources to execute one ormore programs for the respective user, etc.

In addition, in at least some additional embodiments, unused portions ofa single one of the computing nodes 120 (e.g., unused processing unitclock cycles, unused portions of memory, etc.) may be made available foruse by one or more excess capacity users 150, such that one or moreprograms of the one or more excess capacity users may be sharingresources of a single computing node with a dedicated capacity user 140and/or other excess capacity users 150. In addition, in someembodiments, at least some of the computing nodes that are allocated foruse by dedicated capacity users 140 may be made available for use by oneor more variable capacity users 130, such as if it is determined thatsuch access is unlikely to impact dedicated capacity users (e.g., incases where accurate predictions of upcoming demand can be forecast,etc.). Furthermore, in some embodiments, if some amount of computingnodes dedicated for use by one or more dedicated capacity users 140 isoversubscribed (e.g., oversold, and/or provided to one or more otherlong term users), such that the oversubscribed computing nodes areunavailable for the one or more dedicated capacity users 140 at a timethat those users request use of them, then one or more of the programsexecuting on the oversubscribed computing nodes may be migrated to oneor more other computing nodes, such as one or more other computing nodesavailable in one or more remote data centers and/or other computingsystems available for executing the one or more programs, such ascomputing systems provided by another program execution service, etc.

In addition, although some embodiments are described with respect to aprogram execution service and program execution capacity, it will beappreciated that the described techniques may be used to manage accessto various other groups of computing nodes or other types ofcomputing-related resources. A non-exclusive list of examples of othertypes of computing-related resources that may be managed for use bymultiple users may include the following: persistent data storagecapabilities (e.g., on non-volatile memory devices, such as hard diskdrives); temporary data storage capabilities (e.g., on volatile memory,such as RAM); message queuing and/or passing capabilities; other typesof communication capabilities (e.g., network sockets, virtualcommunication circuits, etc.); database management capabilities;dedicated bandwidth or other network-related resources; input devicecapabilities; output device capabilities; processor (e.g., CPU) cyclesor other instruction execution capabilities; etc. For example, a usermay request one or more indicated types of computing-related resourcesto use, and the PESSM module may automatically determine an amount ofeach indicated type of resource (e.g., based on an explicit quantity orother amount indicated by the user in the request, based onpredetermined amounts associated with particular resource types, basedon available amounts of the indicated resource types, etc.) to providefor the user, such as a first amount of volatile memory and a secondamount of persistent storage.

FIG. 1B illustrates an embodiment in which a program execution servicemay be provided using one or more data centers that include multiplephysical computing systems. In particular, FIG. 1B illustrates anexample embodiment in which a PESSM module 180 of a program executionservice manages execution of one or more programs on behalf of users.The illustrated example includes a data center 170 used by the PES thatis connected to the Internet 196 external to the data center 170. Inthis example, the Internet 196 provides access to various externalcomputing systems, such as computing systems 190 via private network 194and other computing systems 192, as well as additional computing systems(not shown) at one or more other data centers 198. The private network194 may be, for example, a corporate network that is wholly or partiallyinaccessible from non-privileged computing systems external to theprivate network 194. Computing systems 192 may include, for example, ahome computing system that connects directly to the Internet (e.g., viaa telephone or cable modem, a Digital Subscriber Line (“DSL”), etc.). Inaddition, the one or more other data centers 198 may further be used bythe PES in at least some embodiments.

The example data center 170 includes a number of physical host computingsystems 175, physical computing systems 182, and the PESSM module 180 ofthe PES. In this example, host computing systems 175 each providesmultiple virtual machines 177 and has a virtual machine (“VM”) managercomponent 179 to manage those virtual machines (e.g., a hypervisor orother virtual machine monitor), and some or all of the computing systems182 may similarly have one or more such virtual machines and/or VMManager components (not shown). Alternatively, in other embodiments,some or all of the physical host computing systems at the data centermay not provide any virtual machines, such as to instead directlyexecute one or more programs on behalf of end user customers of the PES.Furthermore, in some embodiments various of the computing systems 175and 182 may have differing capabilities, may have different associatedfees for use, may support different types of user programs (e.g.,virtual machine software image instances of different sizes, or programswith different types of resource criteria and/or computing resourceusage, such as differing patterns of I/O and memory access and networkusage), etc. If so, particular users and/or their programs may begrouped (e.g., automatically) according to one or more such factors,which may further be used as constraints and/or preferences regardingwhich computing systems to select for executing particular programs. Theexample data center 170 further includes an internal network 172 thatmay include multiple networking devices (not shown), such as switches,edge routers, and core routers, with computing systems 175 and 182 andone or more computing systems (not shown) that execute the PESSM module180 being connected to the internal network 172.

The illustrated PESSM module 180 performs at least some of the describedtechniques in order to manage execution of programs using the computingsystems 175 and 182, as described in greater detail elsewhere. When aparticular computing node or system is selected to execute one or moreprograms of a user, the PESSM module may in some embodiments initiateexecution of those programs by interacting with a VM manager componentor other manager component that controls execution of programs for thatselected computing node/system, or may alternatively directly executethe programs on the selected computing node/system. Users of the PES mayuse various computing systems to interact with the PESSM module 180,such as computing systems 190 or 192, or computing systems at one of theother data centers 198.

It will be appreciated that the data center of FIG. 1B is provided forillustrative purposes only, and that program execution services andother software execution services may be provided in other manners inother embodiments. For example, PESSM module 180 may instead be providedusing one or more other computing systems external to the data center170, such as computing systems 190, 192 or at a data center 198. Inother embodiments, a PES may be provided without using any data centers.

FIGS. 2A and 2B illustrate examples of techniques for managing use ofexcess computing nodes, such as that may be automatically performed byan embodiment of a PESSM module. In particular, FIG. 2A illustrates anexample of receiving and handling requests to use excess computingcapacity from a general excess computing capacity pool, with none of theexample users in FIG. 2A having an associated private excess computingcapacity pool. FIG. 2B continues the example of FIG. 2A, but with one ofthe users having a private excess computing capacity pool, and with thehandling of the various requests including use of that private excesscomputing capacity pool.

With respect to FIG. 2A, table 200 illustrates information about usageof a number of computing nodes 210 of a program execution service byvarious users of the program execution service over time 205, with useof each computing node 210 being illustrated at consecutive timeintervals 205 a-205 o. In addition, table 250 illustrates informationabout example requests A, B, C and D received by the program executionservice to execute programs on behalf of users using excess computingnodes of a general excess computing capacity pool of the programexecution service. In the illustrated table 200, shading is used asfollows: a time interval having a solid gray background (e.g., timeinterval 205 a of dedicated computing node 212 b and time interval 205 hof other computing node 214 a) indicates that the respective computingnode is not available to be used for excess program execution capacityduring that respective interval of time (e.g., it is being used for oneor more other purposes and/or is otherwise not available); a timeinterval having a solid white background (e.g., time intervals 205 b and205 c of dedicated computing node 212 c) or having a diagonal-linedbackground (e.g., time interval 205 f of dedicated computing node 212 band time interval 205 o of other computing node 214 b) indicates thatthe respective computing node is available for use as excess programexecution capacity during that respective interval of time; and a timeinterval containing a letter A, B, C or D (e.g., time intervals 205f-205 k of dedicated computing node 212 a) indicates that programs ofthe respective request for excess program execution capacity areexecuting on the respective computing node during that time interval. Asone illustrative example, each time interval 205 a-205 o may correspondto an hour, or instead to other time intervals (e.g., a day, 10 minutes,etc.).

As previously noted, table 250 illustrates various requests received bythe program execution service at various indicated times, such that eachof the various requests is to execute one or more programs on aspecified amount of excess computing nodes available from the programexecution service using computing nodes 210. In addition, each of therequests has various specified configuration information in thisexample, including a specified minimum and maximum number of computingnodes on which to execute the one or more programs of the request; a bidfee amount that the user is willing to pay for execution of the one ormore programs on each of the computing nodes (e.g., such as a dollaramount per use hour of a single computing node); and an indication of atime at which the request is to expire (e.g., such as a specified totalduration of execution time after which a request is to expire, aspecified time at which a request is to expire, etc.). As oneillustrative example, request A was received at a time thatapproximately corresponds to time interval 205 c (e.g., just before timeinterval 205 c or during time interval 205 c), with a minimum andmaximum number of computing nodes both indicating a preference toexecute on a single excess capacity computing node, with a bid price of$0.05 per hour of use of the single excess computing node, and with nospecified expiration (e.g., indicating that the request is tocontinuously execute and/or re-execute until the program execution iscompleted). In this example, all of the computing nodes 210 may provideapproximately or exactly the same amount of computing capacity per timeinterval, while in other embodiments a standard amount of programexecution capacity may be indicated in other manners (e.g., with alogical ‘computing node’ measure that corresponds to a particular amountof computing resources, and with particular actual computing nodes beingrated as to the number of logical ‘computing nodes’ that they provide.In other embodiments, the various requests may be configured in otherways, such as to include one or more of a specified particular type ofcomputing node to use (e.g., and/or characteristics of such computingnodes), a minimum and/or maximum bid amount, and/or one or more otherconfigurations (e.g., fault tolerance requirements, execution localityand/or proximity preferences, etc.). In addition, other types ofinformation may be indicated in some embodiments, such as one or moreparticular programs to be executed for each request, a total amount ofaggregate computing node time intervals for the request, etc.

The illustrated table 200 includes a number of dedicated capacitycomputing nodes 212, such as computing nodes that have been allocatedfor dedicated access to one or more specific dedicated capacity users ofthe program execution service, and also includes a number of othercomputing nodes 214, such as computing nodes that may be available forother types of program execution capacity (e.g., on-demand variableprogram execution capacity). For example, a dedicated capacity user (notshown) may have priority access to the specific computing node 212 a fora specified period of time (e.g., a year), such that the user may accesscomputing node 212 a to execute programs on behalf of the user at anytime during the specified period of time, although such access may besubject to a delay period and/or one or more interactions on the part ofthe user to gain access (e.g., notifications of an intent to use thecomputing node 212 a at a particular time, a request to execute programson computing node 212 a, etc.). In other embodiments, the dedicatedcapacity user (not shown) may instead have priority access to acomputing node with equivalent computing resources as computing node 212a (e.g., equivalent processing capacity, memory, etc.), but not have aparticular allocated computing node 212, such that the user may beprovided access to any of the computing nodes 212 that are equivalent to212 a for executing programs on behalf of the user and that areavailable for use. In various such embodiments, the program executionservice may ensure that a sufficient number of dedicated computing nodesequivalent to 212 a are available for use by dedicated users who mayhave priority access to such computing nodes in various ways (e.g.,maintaining a group of such computing nodes and/or otherwise reserving aspecific amount of such nodes, etc.).

In table 200, during interval 205 a-c, dedicated computing node 212 chas been determined to be excess capacity, such as based on being unusedby a dedicated capacity user to whom computing node 212 c is allocated,and has thus been made available for use by excess capacity users. Forexample, the dedicated capacity user may have interacted with theprogram execution service to indicate that computing node 212 c isavailable for excess program execution capacity, such as at some timeprior to time interval 205 a, or the program execution service may haveinstead automatically determined that the computing node 212 c wasunused. In the illustrated example, all other of the illustratedcomputing nodes (e.g., 212 a-b, 212 d, and 214 a-b) have not beendetermined to be available during the interval 205 a-205 c. During timeinterval 205 c, request A is received, and the program execution servicedetermines to execute a program associated with request A on theavailable excess capacity computing node 212 c, for the user-specifiedfee of $0.05/hour, and initiates execution of the program on computingnode 212 c. In other embodiments, the program execution service mayinstead have a fixed price fee that some or all excess capacity usersuse.

At time interval 205 d, the program execution service determines thatcomputing node 212 c is no longer available to satisfy excess programexecution capacity requests (e.g., based on an indication received froma dedicated capacity user reclaiming use of the computing node), and sothe execution of the program associated with request A is terminated oncomputing node 212 b. At interval 205 f, the program execution servicedetermines that two computing nodes with sufficient resources to executerequest A (e.g., dedicated computing nodes 212 a and 212 b) areavailable as excess capacity computing nodes, and determines toreinitiate execution of request A's program on dedicated computing node212 a. In the illustrated embodiment, the diagonal lines at timeinterval 205 f with respect to dedicated computing node 212 b indicatethat node 212 b is available during that time interval for use as excesscomputing capacity, but is not preferred for excess computing capacityuse, and thus is not selected to satisfy request A. Computing node 212 bis not preferred for various reasons, such as it having a short and/oruncertain duration of availability (e.g., as determined by the programexecution service, such as based on indications from the dedicatedcapacity user to whom it is allocated, based on prior history of use,based on forecasted use, etc.), whereas node 212 a may be determined tohave an availability that is likely to be relatively longer than node212 b. In such a situation, the program execution service may have apreference for selecting a computing node with a longer likelyavailability for executing a request of an excess capacity user, such asto minimize having to start/stop execution programs on the variouscomputing nodes 210, etc. Thus, in this example, computing node 212 b isnot used during time interval 205 f, but if another excess computingcapacity request had been received prior to time interval 205 f, node212 b may have nonetheless been used for that other request.

In this example, request B is received at interval 205 g, as illustratedby table 250. In this case, there is only one excess computing nodeavailable at that time (e.g., dedicated computing node 212 a), and theprogram execution service determines to terminate the execution of theprogram for request A in lieu of the program of request B, such as basedon request B having a higher bid amount (e.g., $0.08/hour) than requestA (e.g., $0.05/hour) or otherwise having a higher priority. In thisexample, request B is executed continuously on dedicated computing node212 a for a fee of $0.08/hour over the time intervals 205 g-205 i. Attime interval 205 i, two computing nodes are available as excesscomputing nodes (dedicated computing nodes 212 a and 212 d), each havingsufficient resources for executing the program for request B—sincerequest B specifies a maximum of two computing nodes, the program ofrequest B remains executing on node 212 a in the illustrated embodiment,and is also initiated on node 212 d.

At time interval 205 j, three dedicated computing nodes are determinedto be available as excess capacity computing nodes (computing nodes 212a, 212 c and 212 d), and request C is received. In this embodiment, theprograms of request B are terminated from execution on dedicatedcomputing nodes 212 d and 212 a, and one or more programs associatedwith request C are executed on all three of the available excesscomputing nodes based on request C having an indicated preference toexecute on a maximum of three nodes and having a relatively higher bidamount (e.g., $0.10/hour) than requests A and B, thus providing a higherpriority for request C than for requests A and B. At time interval 205k, two dedicated computing nodes are determined to be available asexcess computing nodes (computing nodes 212 a and 212 c), such as basedon computing node 212 d having been reclaimed for other purposes orotherwise having become unavailable. The one or more programs associatedwith request C are terminated on computing node 212 d but remainexecuting on nodes 212 a and 212 c, such as based on the preferredmaximum and minimum number of computing nodes for request C, and requestC having a higher priority than requests A and B. The program(s) ofrequest C continue to execute on computing node 212 c at time interval205 l, but the execution on computing node 212 a is terminated due tothe computing node becoming unavailable for excess computing capacityuse. After time interval 205 l, the program execution service determinesthat request C has executed for at least three hours over the timeintervals 205 j-205 l, and has thus expired. Accordingly, the programexecution service terminates execution of the programs associated withrequest C on the excess capacity computing nodes, and request C is nolonger treated as a pending request to be satisfied. At time interval205 m, one computing node (dedicated computing node 212 c) is determinedto continue to be available for use as excess program executioncapacity, and the execution of the program associated with request B isreinitiated on the computing node.

During time interval 205 m, the execution of the program(s) for requestB ends (e.g., based on the program(s) completing their execution after 5aggregate hours of execution, or instead based on an instructionreceived (not shown) to cancel request B from the excess capacity userwho submitted request B), and request B is treated as no longer being apending request to be satisfied. In addition, at or near this time,request D is received, having a bid amount equivalent to previouslyreceived request A (e.g., $0.05/hour). In this case, the programexecution service determines to reinitiate execution of the programassociated with request A on available dedicated computing node 212 c atnext time interval 205 n rather than the program associated with requestD, based on request A having been received at an earlier time than D.Request A continues to execute on node 212 c until some unknown futuretime after time interval 205 o. At interval 205 o, one of the othercomputing nodes 214 b becomes available for use as excess programexecution capacity, and is determined to be a non-preferred excesscapacity computing node, but the program of request D is nonethelessexecuted on the other computing node 214 b since no other excesscomputing nodes are currently available.

In the illustrative example of FIG. 2A, the program execution servicemay further track usage of the computing nodes 210 corresponding to thevarious requests A-D, such that the various associated users are chargedfees corresponding to the bid amounts indicated by the various requests.In addition, the program execution service may also track which of thecomputing nodes 210 were used and/or were made available for use byexcess capacity users, such that one or more users associated with thosecomputing nodes may be given some portion of the fees collected from theexcess capacity users.

FIG. 2B continues the example of FIG. 2A, but with one of the usershaving a private excess computing capacity pool, and with the handlingof the various requests including use of that private excess computingcapacity pool. FIG. 2B illustrates information 200 and 250 in a mannersimilar to that of FIG. 2A, but with some changes to reflect the use ofthe private excess computing capacity pool, as discussed below. Inaddition, new information 260 and 270 has been added to FIG. 2B relativeto FIG. 2A.

In particular, in the example of FIG. 2B, the user who submits request B(referred to as Requester B* in FIG. 2B) is also a dedicated capacityuser, and has been allocated the dedicated use of computing node 212 afor a time period that includes time intervals 205 a-205 o, as shown byinformation 270. Accordingly, in FIG. 2B, the shading for computing node212 a has been changed to include crosshatching to reflect that anyunused capacity of computing node 212 a is available for use as aprivate excess capacity pool for Requester B*. In this example, the timeintervals of 205 a-205 e and 205 l-205 o for computing node 212 acorrespond to dedicated use of computing node 212 a by Requester B*, andthus computing node 212 a is available during the time intervals of 205f-205 k for use as part of the private excess computing capacity poolfor Requester B*. As discussed in greater detail elsewhere, requestsfrom Requester B* have priority for use of the private excess computingcapacity pool.

The assignments for time intervals 205 a-205 i are the same in FIG. 2Bas in FIG. 2A. For example, request B from Requester B* was alreadyassigned to use computing node 212 a for time intervals 205 g-205 i inFIG. 2A, based on request B having a higher priority for the generalexcess computing capacity pool in FIG. 2A than request A, and thus theuse of computing node 212 a for the private excess computing capacitypool in FIG. 2B does not alter those prior assignments. However, afterrequest C is received for time interval 205 j, the assignments change inFIG. 2B relative to FIG. 2A based on the use of the private excesscomputing capacity pool. In particular, in FIG. 2A, request C was givenhigher priority than requests A and B for the general excess computingcapacity pool, and thus all three excess computing capacity nodesavailable at time interval 205 j in FIG. 2A began to execute theprogram(s) for request C. With respect to FIG. 2B, however, request Bfrom Requester B* continues to have the highest priority at timeinterval 205 j for the excess computing capacity in Requester B*'sprivate excess computing capacity pool—accordingly, the program(s) forrequest C similarly begin to execute on computing nodes 212 c and 212 dat time interval 205j in FIG. 2B, but the program(s) for request Bcontinue to execute on computing node 212 a at that time interval inFIG. 2B in a manner different from that of FIG. 2A. In particular, sincea request from Requester B* is available at time interval 205 j, thatrequest (in this example, request B) is given priority to use the excesscomputing capacity of computing node 212 a that is part of RequesterB*'s private excess computing capacity pool. Similarly, at thesubsequent time interval 205 k, if the program(s) for request B hadcontinued to execute, those program(s) would have continued to executeon computing node 212 a for the same reasons, based on the higherpriority of request B than request C for the private excess computingcapacity pool of Requester B*. However, in this example, since request Bends after 5 aggregate hours of program execution, the program(s) ofrequest B end after time interval 205 j. Accordingly, the excesscomputing capacity for computing node 212 a at time interval 205 kreturns to the general excess computing capacity pool, and theprogram(s) of request C begin to execute on computing node 212 a fortime interval 205 k.

Thus, the use of the private excess computing capacity pool providesvarious benefits for Requester B* in the example of FIG. 2B. Forexample, as a first benefit, request B is completed more rapidly in theexample of FIG. 2B, in particular by the end of time interval 205 j inFIG. 2B rather than the end of time interval 205 m in FIG. 2A. Inaddition, as a second benefit in the example of FIG. 2B, the performanceof request B is performed more cheaply for Requester B* than theperformance of request B in FIG. 2A. In particular, in the example ofFIG. 2B, the use of the private excess computing capacity pool byRequester B* is charged to Requester B* at the same rate as theincremental on-going cost of using dedicated computing node 212 a, whichin this example is $0.04 per time interval hour, as shown in information270. Thus, while the performance of request B in FIG. 2A would have costthe request B bid price of $0.08 per time interval hour (i.e., twicethat amount for each time interval hour as the incremental on-going costof using dedicated computing node 212 a) for each of the 5 aggregatehours of execution of the program(s) for request B, in FIG. 2B the costfor performing request B is only $0.04 per time interval hour for thefour of the five aggregate hours in which the private excess computingcapacity pool was used, as shown in cost information 260 g-260 j. Forthe other time interval hour during which request B is executed oncomputing node 212 d in FIG. 2B as part of the general excess computingcapacity pool, the cost is charged at the request

B bid price of $0.08 per time interval hour, as shown in costinformation 260 z. Thus, the total cost for performing request B in FIG.2B is $0.24, while the total cost for performing request B in FIG. 2A is$0.40. While the absolute numbers are small in this example based on thelimited amount of use of excess computing capacity, it will beappreciated that increasing such excess computing capacity by asignificant amount in a real-world situation may result incorrespondingly larger actual cost savings (e.g., if use is increased athousand-fold, the corresponding savings would be ˜$1600 in thisexample, based on actual costs of $2400 rather than $4000).

Furthermore, in other situations, request B may be performed even morecheaply than in the example of FIG. 2B. For example, in FIG. 2B, one ofthe five aggregate hours of execution of the program(s) of request B(i.e., 20% of the total aggregate hours of execution) was performedusing the general excess computing capacity pool (i.e., use of the timeinterval of 205 i for computing node 212 d), and an available other hourfrom the private excess computing capacity pool (i.e., time interval 205k for computing node 212 a) was not used. Thus, in other situations, theexecution of the program(s) for request B may instead use the privateexcess computing capacity pool for all of the execution of theprogram(s) for request B, and thus be charged at the lower cost of theprivate excess computing capacity pool for all of that execution. Suchuse of the private excess computing capacity pool may be triggered by,for example, request B having instead specified a maximum of onecomputing node (so that only the private excess computing capacity poolis used if it is available). Alternatively, in other embodiments,Requester B* may specify that request B (or one or more other requests)is only to be executed using his/her private excess computing capacitypool, rather than to also use the general excess computing capacity poolas a supplement to the private excess computing capacity pool.

In addition, in some embodiments, the private excess computing capacitypool may further be used in other manners to provide other benefits. Forexample, consider a situation similar to that of FIG. 2B, but in whichrequest B has a higher priority than request C for use of the generalexcess computing capacity pool (e.g., if request C has a bid price of$0.07 rather than $0.10), in which request B uses six aggregate hours tocomplete execution of its program(s) rather than five aggregate hours,and in which request B specifies to use a maximum of one computing noderather than two. In such a situation, and using the allocation schemepreviously described for FIG. 2B, request B would not be selected to usecomputing node 212 d in time interval 205 i from the general excesscomputing capacity (given the maximum of one computing node and thepreference for using the private excess computing capacity pool), butwould be selected to continue to use computing node 212 a in timeinterval 205 k from the private excess computing capacity pool. However,in that situation, at the end of time interval 205 i, request B wouldstill have 1 additional hour of execution until completion, but theavailability of computing node 212 a in the private excess computingcapacity pool at time interval 205 l would disappear based on theresumed use of dedicated capacity by Requester B* at that time interval.Thus, one option in that situation would be to terminate the executionof the program(s) for request B on computing node 212 a at the end oftime interval 205 k, and to immediately resume the execution of thoseprogram(s) for one additional hour on computing node 212 c during timeinterval 205 l. However, in other embodiments, other possible actionsmay be taken. For example, to avoid the overhead of terminating and thenrestarting the execution of the program(s) for request B when only ashort time remains until completion, those program(s) for request Bcould instead be allowed to complete their execution on computing node212 a during some or all of time interval 205 l. While Requester B*'sdesire to resume dedicated capacity use in time interval 205 l could bedeferred in this situation, an alternative that accommodates such aresumption of dedicated capacity use in time interval 205 l includesselecting another computing node to temporarily use for Requester B*'sdedicated capacity use during at least time interval 205 l, such ascomputing node 212 c. In this manner, Requester B* receives the desireddedicated capacity use in time interval 205 l, and the execution of theprogram(s) for request B is allowed to complete more efficiently andquickly. Nonetheless, in such an example, the use of computing node 212a during time interval 205 l for the completion of the execution of theprogram(s) for request B may not be treated for cost purposes in atleast some such embodiments as being part of the private excesscomputing capacity pool, such that Requester B* may receive thededicated capacity use price of $0.04 for the use of computing node 212c during time interval 205 l, but the execution of the program(s) forrequest B using computing node 212 a during time interval 205 l may becharged at the general excess computing capacity pool price of $0.08 toreflect request B's bid price. It will be appreciated that otheralternatives may similarly be used in other embodiments and situations.

In addition, it will be appreciated that the preceding examples areprovided for illustrative purposes, and that other embodiments maydiffer in various ways from the example. For example, although thecomputing nodes 210 are depicted as being equivalent (e.g., havingequivalent computing resources), other embodiments may be provided wherevarious of the computing nodes 210 may be of different types withvarying characteristics (e.g., different amounts of processing capacity,memory, platform specification, etc.). In some such embodiments, variousof the requests may include indications of one or more specific types ofthe computing nodes for use in executing programs associated with therequests, and those requests may only be executed on the correspondingspecified type of computing node. In addition, in some embodiments,rather than excess computing capacity being based on unused dedicatedcomputing nodes and other computing nodes as illustrated, embodimentsmay exist where only one group of computing nodes and/or additionalgroups of computing nodes may contribute to excess capacity computingnodes available for executing requests of excess capacity users.Furthermore, in some embodiments, at least some of the other computingnodes 214 may include computing nodes provided to the program executionservice by one or more third parties.

As previously discussed, various types of functionality may be providedand used by a PES in various embodiments, and the functionality may beprovided in various ways. For example, in some embodiments, programexecution capacity available from a PES may include multiple computingnodes for executing programs on behalf of users, such as via multiplephysical computing machines interconnected via one or more networks orother data exchange mediums that are capable of transmitting databetween the computing machines. At least some of the computing machinesmay in some embodiments each include sufficient computing-relatedresources to execute multiple programs simultaneously (e.g., sufficientwriteable memory, non-volatile storage, CPU cycles or other CPU usagemeasure, network bandwidth, swap space, etc.), and at least some of thecomputing machines in some such embodiments may each host multiplevirtual machine computing nodes that each may execute one or moreprograms on behalf of a distinct user. Furthermore, in variousembodiments, a PES may execute various types of programs on behalf ofmultiple users. For example, such programs executed on behalf of usersmay include one or more operating systems, applications (e.g., serversand/or other software applications), utilities, libraries, etc. Inaddition, in at least some embodiments, such programs may includeexecutable software images, such as virtual machine images that arebootable or otherwise loadable on one or more virtual machine computingnodes, and that each may include operating system software, software forone or more application programs, and/or configuration information, etc.

In at least some embodiments, the execution of one or more programs onone or more computing nodes by a PES may be initiated in response to acurrent execution request for immediate execution of those programs.Alternatively, the initiation may be based on a previously receivedprogram execution request that scheduled or otherwise reserved thethen-future execution of those programs for the now-current time.Program execution requests may be received in various ways, such asdirectly from a user (e.g., via an interactive console or other GUIprovided by the program execution service), or from an executing programof a user that automatically initiates the execution of one or moreother programs or other instances of itself (e.g., via an API, orapplication programming interface, provided by the program executionservice, such as an API that uses Web services). Program executionrequests may include various information to be used in the initiation ofthe execution of one or more programs, such as an executable or othercopy of a program to be executed, an indication of a program that waspreviously registered or otherwise supplied for execution, and a numberof instances of the program that are to be executed simultaneously(e.g., expressed as a single desired number of instances, as a minimumand maximum number of desired instances, etc.), as well as a variety ofother types of preferences and/or requirements for execution of one ormore programs (e.g., resource allocation, geographical and/or logicallocation for execution, proximity of execution to other programs and/orcomputing nodes, timing-related criteria, etc.).

After receiving a request to execute one or more instances of a programat an indicated time, the PES may determine one or more computing nodesto use in executing the program instances. In some embodiments, thedetermination of the computing nodes to be used is performed at the timeof the request even if for future execution. In other embodiments, thedetermination of the computing nodes to be used for future execution ofone or more program instances may be deferred to a later time, such asat the future time of execution based on information that is thenavailable. In some embodiments, the determination of which computingnodes to use for execution of one or more programs on behalf of a usermay be made prior to a request to execute, such as at a time when a usersubscribes and/or registers to use the PES, and/or at another time priorto a request to execute programs for a user. For example, in some suchembodiments, one or more computing nodes may be associated with a userfor a period of time, such that programs may be executed on behalf ofthat user on the associated computing nodes at any time during thatperiod, such as at any time a request is received to execute softwarefor the user during the period. In addition, in some embodiments, thedetermination of which computing nodes to use to execute programs onbehalf of a user may be made when one or more computing nodes and/orcomputing resources of one or more computing nodes become available forexecuting programs for the user, such as, for example to executeprograms of one or more pending requests on one or more computing nodesat a time when the computing nodes are unused and/or are otherwiseavailable for executing the programs.

The determination of which computing nodes to use for execution of eachprogram instance may be made in a variety of ways, including based onany preferences and/or requirements specified in the request orotherwise specified for the program and/or associated user (e.g., at atime of registration, etc.). For example, if criteria are determined forpreferred and/or required resources for execution of a program instance(e.g., memory and/or storage; CPU type, cycles or other performancemetric; network capacity; platform type, etc.), the determination of anappropriate computing node to execute a program instance may be based atleast in part on whether a computing node has sufficient resourcesavailable to satisfy those resource criteria. Additional details relatedto executing and configuring programs to execute on a program executionservice are included in pending U.S. patent application Ser. No.11/395,463, filed Mar. 31, 2006 and entitled “Managing Execution ofPrograms by Multiple Computing Systems,” which is hereby incorporated byreference in its entirety.

In addition, as previously noted, in at least some embodiments,execution of a program using excess program execution capacity that isautomatically terminated may be automatically reinitiated at a latertime by the PES. For example, in some such cases, the PES may continueto try to execute a program until completion of the requested execution(e.g., until cancelled or otherwise explicitly terminated by a user,until an indication is received that the one or more programs havecompleted one or more tasks, etc.), until occurrence of a specified time(e.g., until occurrence of an expiration time, until occurrence of acumulative execution time, etc), until occurrence of a specified numberof executions, indefinitely, etc.

In some embodiments, fees may be associated with the use of a PES, suchthat the PES may execute programs on behalf of a user in exchange forpayment of one or more fees by that user. For example, in someembodiments, fees may be charged to a user based on an amount and/ortype of program execution capacity allocated for executing one or moreprograms on behalf of a user, such as based on one or more of a numberof processing units, an amount of memory, an amount of storage, anamount of network resources, etc., allocated for executing programs ofthe user. In some embodiments, fees may be based on other factors, suchas various characteristics of the computing resources used to executeprograms, such as, for example, based on CPU capabilities orperformance, platform type (e.g., 32-bit, 64-bit, etc.), etc. In someembodiments, fees may be charged on the basis of a variety of usefactors, such as a price per use of the service, a price per unit oftime that computing services are used, a price per storage used, a priceper data transferred in and/or out, etc. In at least some embodiments,as discussed in more detail below, fees may be based on various otherfactors, such as related to availability of the program executioncapacity (e.g., varying degrees of availability, such as guaranteedavailability and/or variable availability) and/or various propertiesrelated to executing programs (e.g., continuity of execution, faulttolerance, etc.). In at least some embodiments, a provider of a PES mayoffer one or more of various tiers, types and/or levels of services orfunctionality for executing programs on behalf of multiple users, and insome such embodiments, various fees may be associated with the varioustiers, types and/or levels of services. For example, in someembodiments, a user may be charged one or more fees in conjunction withuse of dedicated program execution capacity functionality provided by aPES, such as fees that are respectively lower than fees associated withcomparable use of an on-demand variable program execution capacityservice of the PES. The lower fees may reflect, for example, the userentering into a long-term agreement for a specified use time period(e.g., a number of weeks, months, years, etc.), such as to pay one ormore specific rates over the term of the agreement (e.g., up frontand/or periodically). In addition, for example, tiers may be used for aspecific type of functionality provided by a PES, such as to charge feesat a first tier for a first quantity of dedicated program executioncapacity functionality (e.g., up to a specified first threshold ofcomputing nodes being used), to charge fees at a second tier (e.g., alower price tier) for a second quantity of dedicated program executioncapacity functionality (e.g., above the specified first threshold and upto a specified second threshold of computing nodes being used), etc.Tiers may further be based on various factors other than quantity offunctionality that is used in at least some embodiments, whether insteadof or in addition to being based on quantity of functionality used.Additional details related to various fees associated with a programexecution service are included in pending U.S. patent application Ser.No. 11/963,331, filed Dec. 21, 2007 and entitled “Providing ConfigurablePricing for Execution of Software Images,” which is hereby incorporatedby reference in its entirety.

A use time period for a period of dedicated computing capacity may bespecified in various manners in various embodiments, such as to indicatea specified period of time in which a user has access to dedicatedprogram execution capacity (e.g., a number of days, weeks, months,years, etc.), a duration of time in which one or more programs may becontinuously executed for a user (e.g., a number of hours the one ormore programs may execute within any given period, such as an hour aday, an hour a week, etc.), a window of time in which one or moreprograms may execute (e.g., between 1:00 p.m. and 3:00 p.m. every otherday), etc. As previously noted, in some embodiments an electronicmarketplace may be provided for users of a PES, such that dedicatedprogram execution capacity users may provide some or all of theirspecified use time period for dedicated program execution capacity toone or more other users in exchange for payment from those one or moreother users, such that the one or more other users may use the providedportions of dedicated program execution capacity to execute programs onbehalf of the one or more other users, and the dedicated programexecution capacity user may receive payment for such use. In otherembodiments, a dedicated program execution capacity user may temporarilyprovide use of some portion of her dedicated program execution capacityfor use by one or more users based in part on the one or more otherusers having an urgent need of the program execution capacity, such asindicated by a willingness of the one or more users to pay a premium foruse of the dedicated program execution capacity (e.g., a rate greaterthan that paid by the dedicated program execution capacity user), and inat least some such embodiments a portion and/or all of the feescollected from the one or more users may be provided to the dedicatedcapacity user.

Furthermore, various other types of functionality may be provided andused by a PES in various embodiments, as discussed in greater detailelsewhere.

FIG. 3 is a block diagram illustrating an example embodiment of a systemsuitable for performing techniques to manage use of computing nodes bymultiple users. In particular, FIG. 3 illustrates a server computingsystem 300 suitable for executing an embodiment of a Program ExecutionService System Manager module, as well as various user computing systems350, computing nodes 360, and other computing systems 380. In theillustrated embodiment, the server computing system 300 has componentsthat include a CPU 305, various I/O components 310, storage 320, andmemory 330. The illustrated I/O components include a display 311, anetwork connection 312, a computer-readable media drive 313, and otherI/O devices 315 (e.g., a keyboard, a mouse, speakers, etc.). Inaddition, the illustrated user computing systems 350 have componentssimilar to those of server computing system 300, including a CPU 351,I/O components 352, storage 354, and memory 357, although some detailsare not illustrated in this example for the sake of brevity. The othercomputing systems 380 and computing nodes 360 may also each includesimilar components to some or all of the components illustrated withrespect to server computing system 300, but such components are notillustrated in this example for the sake of brevity.

An embodiment of a Program Execution Service System Manager module 340is executing in memory 330, and it interacts with computing systems 350and 380 and computing nodes 360 over the network 390 (e.g., via theInternet and/or the World Wide Web, via a private cellular network,etc.). In this example embodiment, the PESSM 340 may, for example,include software instructions that when executed program one or moreprocessors (e.g., CPU 305) to perform some or all of the describedtechniques, including functionality related to managing use of multiplecomputing nodes 360 by various users (not shown) interacting with usercomputing systems 350, such as in conjunction with a program executionservice managed by the PESSM 340. The other computing systems 350 and380 and computing nodes 360 may be executing various software as part ofinteractions with the PESSM. For example, user computing systems 350 maybe executing software in memory 357 to interact with PESSM 340 (e.g., aspart of a Web browser or specialized client-side application program),such as to configure and/or request execution of programs on behalf ofthe users of those systems on one or more computing nodes 360 in variousways, such as related to variable execution capacity use, dedicatedexecution capacity use, and/or excess execution capacity use. Inaddition, one or more users of the user computing systems 350 mayinteract with PESSM 340 to perform various other types of actions, asdiscussed in greater detail elsewhere. Various information related tothe functionality of the PESSM module 340 may be stored in storage 320,such as information 324 related to private excess capacity pools (e.g.,tracked current availability, user instructions related to configurationand/or other configuration information, etc.) and other information 322(e.g., information related to configuration, execution and/orregistration for executing programs on behalf of multiple users).

In this example, the PESSM module 340 includes three constituentmodules, including a Dedicated Capacity Usage Manager module 342, anExcess Capacity Usage Manager module 344, and an On-Demand VariableCapacity Usage Manager module 346. The Dedicated Capacity Usage Managermodule 342 manages the use of dedicated computing capacity by users,with FIG. 6 illustrating a routine corresponding to operations of themodule 342 in one example embodiment. The Excess Capacity Usage Managermodule 344 manages the use of general and private excess computingcapacity pools by users, with FIGS. 5A and 5B illustrating a routinecorresponding to operations of the module 344 in one example embodiment.The On-Demand Variable Capacity Usage Manager module 346 manages the useof on-demand variable computing capacity by users, with FIG. 7illustrating a routine corresponding to operations of the module 346 inone example embodiment. In other embodiments, the functionality providedby the PESSM module 340 may be structured in other manners, including tooptionally not include one or more of the constituent modules 342-346(e.g., to not include the On-Demand Variable Capacity Usage Managermodule 346 for an embodiment that does not provide on-demand variablecapacity usage).

After the PESSM module 340 receives a request (or other indication) toexecute one or more programs on one or more computing nodes 360, thePESSM module 340 determines a constituent module 342-346 thatcorresponds to the indicated type of program execution capacity to use,and forwards the request to the determined constituent module. Thedetermined constituent module and the PESSM module 340 then performvarious operations to respond to the request, such as selecting the oneor more computing nodes that will execute the one or more programs, andinitiating execution of those programs on those computing nodes 360. Inaddition, the PESSM module 340 (including constituent modules 342-346)may further perform operations to interact with computing nodes 360 toterminate execution of initiated programs on the computing nodes, tomigrate one or more of the programs to one or more other computing nodes360 or computing systems 380, to monitor or otherwise interact with oneor more of the computing nodes 360 to track use of those computingnodes, etc. The computing nodes 360 may have various forms in variousembodiments, such as to include a number of physical computing systemsand/or a number of virtual machines executing on one or more physicalcomputing systems. In some embodiments, the server computing system 300and computing nodes 360 may be part of a data center or other group ofco-located computing systems, or may otherwise be computing nodes of aprivate network. In addition, in some embodiments, the PESSM module 340may interact with one or more other computing systems 380 to initiate orterminate execution of one or more programs on those computing systems,such as if the computing systems 380 are provided by one or morethird-party participants who are providing excess program executioncapacity for use by other users. In some embodiments, the PESSM module340 may further or instead manage access to one or more types ofcomputing-related resources or services other than program executionservices (e.g., persistent or temporary data storage services, messagingservices, database services, etc.).

It will be appreciated that computing systems 300, 350 and 380 andcomputing nodes 360 are merely illustrative and are not intended tolimit the scope of the present invention. The computing systems and/ornodes may instead each include multiple interacting computing systems ordevices, and the computing systems/nodes may be connected to otherdevices that are not illustrated, including through one or more networkssuch as the Internet, via the Web, or via private networks (e.g., mobilecommunication networks, etc.). More generally, a computing node or othercomputing system may comprise any combination of hardware or softwarethat may interact and perform the described types of functionality,including without limitation desktop or other computers, databaseservers, network storage devices and other network devices, PDAs,cellphones, wireless phones, pagers, electronic organizers, Internetappliances, television-based systems (e.g., using set-top boxes and/orpersonal/digital video recorders), and various other consumer productsthat include appropriate communication capabilities. In addition, thefunctionality provided by the illustrated PESSM module 340 and itsconstituent modules may in some embodiments be distributed in additionalmodules or combined in fewer modules. Similarly, in some embodiments,some of the functionality of the PESSM module 340 may not be providedand/or other additional functionality may be available.

It will also be appreciated that, while various items are illustrated asbeing stored in memory or on storage while being used, these items orportions of them may be transferred between memory and other storagedevices for purposes of memory management and data integrity.Alternatively, in other embodiments some or all of the software PESSMmodule 340 and/or constituent modules may execute in memory on anotherdevice and communicate with the illustrated computing systems viainter-computer communication. Furthermore, in some embodiments, some orall of the PESSM module 340 and/or constituent modules may beimplemented or provided in other manners, such as at least partially infirmware and/or hardware, including, but not limited to, one or moreapplication-specific integrated circuits (ASICs), standard integratedcircuits, controllers (e.g., by executing appropriate instructions, andincluding microcontrollers and/or embedded controllers),field-programmable gate arrays (FPGAs), complex programmable logicdevices (CPLDs), etc. Some or all of the modules and data structures mayalso be stored (e.g., as software instructions or structured data) on acomputer-readable medium, such as a hard disk, a memory, a network, or aportable media article to be read by an appropriate drive or via anappropriate connection. The modules and data structures may also betransmitted as generated data signals (e.g., as part of a carrier waveor other analog or digital propagated signal) on a variety ofcomputer-readable transmission mediums, including wireless-based andwired/cable-based mediums, and may take a variety of forms (e.g., aspart of a single or multiplexed analog signal, or as multiple discretedigital packets or frames). Such computer program products may also takeother forms in other embodiments. Accordingly, the present invention maybe practiced with other computer system configurations.

FIG. 4 is a flow diagram of an example embodiment of a Program ExecutionService System Manager routine 400. The routine may be provided by, forexample, execution of the PESSM modules 110 and 180 of FIGS. 1A and 1B,respectively, a PESSM module (not shown) that performs operationscorresponding to FIGS. 2A and 2B, and/or the PESSM module 340 of FIG. 3,such as to assist in managing use of multiple computing nodes and/orother types of program execution capacity, as well as to perform othertypes of management operations in some situations. In this illustratedembodiment, the routine 400 manages various aspects of use of a programexecution service that provides program execution capacity for executingprograms on behalf of multiple users.

In the illustrated embodiment, the routine begins at block 405, whereinformation or a request is received. The routine continues to block 410to determine if the received request or information is related todedicated capacity use. If so, the routine continues to block 415 toperform a routine related to managing dedicated computing capacityusage, with one example embodiment of such a routine being discussed ingreater detail with respect to FIG. 6. If it is instead determined atblock 410 that the information or request of block 405 is not related todedicated capacity use, the routine continues to block 430 to determineif the information or request is related to excess computing capacityuse. If so, the routine continues to block 435 to perform a routinerelated to managing excess computing capacity usage, with one exampleembodiment of such a routine being discussed in greater detail withrespect to FIGS. 5A-5B. If it is instead determined at block 430 thatthe information or request of block 405 is not related to excesscapacity use, the routine continues to block 440 to determine if theinformation or request is related to on-demand variable computingcapacity use. If so, the routine continues to block 445 to perform aroutine related to managing on-demand variable computing capacity usage,with one example embodiment of such a routine being discussed in greaterdetail with respect to FIG. 7.

If it is instead determined at block 440 that information or a requestrelated to variable capacity use is not received, the routine continuesto block 460 to determine if the information or request is related to asecondary dedicated capacity market, and if so, the routine continues toblock 462 to perform one or more indicated operations as appropriaterelated to a secondary dedicated capacity market. For example, invarious embodiments, such operations may include one or more ofindications from dedicated capacity users to sell and/or rent variousamounts of the users' dedicated program execution capacity, indicationsfrom one or more other users to buy and/or rent program executioncapacity from dedicated capacity users, indications from one or moreurgent users who may be willing to pay a premium for various amounts ofprogram execution capacity, etc.

After blocks 415, 435, 445 and 462, or if it is instead determined inblock 460 that information or a request related to a secondary dedicatedcapacity market is not received, the routine continues to block 470 tooptionally perform any user billing or reimbursement activities based onthe information or request received in block 405 or as is otherwiseinitiated (e.g., periodically), such as to charge and/or collect feesfrom one or more users (e.g., dedicated capacity users, variablecapacity users, excess capacity users, and/or others) based on programexecution functionality provided to the users, and/or to pay and/orreimburse one or more users (e.g., dedicated capacity users and/orothers who provided computing resources for use by excess capacityusers, etc.) for functionality provided by or enabled by the users.

After block 470, the routine continues to block 475 to optionallymonitor for excess program execution capacity for any general excesscomputing capacity pools and private excess computing capacity pools inuse, such that program execution capacity may be added and/or removedfrom the excess program execution capacity available for use by one ormore excess capacity users. In other embodiments, the routine mayreceive other indications of current and/or expected usage of programexecution capacity, such as notifications from one or more computingresources of the program execution service (e.g., such as computingnodes with resident monitors that may indicate current usage status),notifications from one or more users, and/or may otherwise determinewhen computing resources are and/or are likely to be used, unused, orunderutilized.

Next, the routine continues to block 495 to optionally perform one ormore other indicated operations. In some embodiments, such operationsmay include configuring use of various resources and/or functionality ofthe program execution service for users, subscription or registrationoperations, scheduling operations, etc. After block 495, the routinecontinues to block 498 to determine whether to continue, such as untilan explicit indication to terminate execution of the routine isreceived. If so, the routine returns to block 405, and if not, theroutine continues to block 499 and ends.

FIG. 6 is a flow diagram of an example embodiment of a DedicatedCapacity Usage Manager routine 600. The routine may be provided by, forexample, execution of the Dedicated Capacity Usage Manager module 342 ofthe PESSM module 340 of FIG. 3, or as part of the PESSM modules 110 and180 of FIGS. 1A and 1B, respectively, and/or a PESSM module (not shown)that performs operations corresponding to FIGS. 2A and 2B, and may beinitiated from block 415 of routine 400 in FIG. 4, or otherwise invoked.

In the illustrated embodiment, the routine 600 begins at block 605,where a request, information and/or other indication related todedicated capacity use is received. At block 612, the routine thendetermines whether a request has been received from a user to subscribefor use of dedicated program execution capacity. If so, the routinecontinues to block 614 where corresponding information is obtained froma subscribing user, and various operations related to subscribing foruse of dedicated program execution capacity are performed. For example,in some embodiments, a user may select and/or indicate one or morecomputing nodes to which the user would like dedicated access. Asdiscussed elsewhere, in some embodiments, a user may select from one ormore of various types of computing nodes and/or may otherwise specifyvarious amounts and/or types of computing resources desired (e.g.,processing unit type/amount, memory amount, platform specification,etc.). In addition, a subscribing user may also indicate a desired timeperiod of use over which the user would like dedicated access (e.g., anumber of hours, weeks, months, years, etc.), and/or may provide otherinformation (e.g., billing information, indications of programs toexecute on behalf of the user, scheduling information for executing oneor programs at one or more future times, etc.). After the subscriberprovides information related to a type and/or amount of desireddedicated program execution capacity, the routine continues to block 616where an appropriate amount of requested program execution capacity isallocated for dedicated use by the subscribing user if possible. Asdiscussed elsewhere, program execution capacity (e.g., one or morecomputing nodes) may be allocated and/or assigned for use by aparticular subscribing dedicated capacity user in various ways invarious embodiments.

After block 616, the routine continues to block 618 to optionallydetermine whether to use at least some of the computing capacityallocated to the subscriber for dedicated use as part of a private poolof excess computing capacity for use by the subscriber (and/or by otherdesignated users), and if so to store corresponding information toenable use of the private excess computing capacity pool. For example,in some embodiments, private excess computing capacity pools may beenabled and used for decided capacity subscriber users, such that alldedicated computing capacity that is allocated to such a user may bemade available for possible later use in a private excess computingcapacity pool for that user while that dedicated computing capacity isnot otherwise being used by the user. Alternatively, the PESSM modulemay in some embodiments create such private excess computing capacitypools for all dedicated capacity users by default unless otherwiseinstructed. In other embodiments, such a private excess computingcapacity pool for a dedicated capacity user may not be created in block618 unless the user provides explicit instructions to do so, and/orother predetermined criteria are satisfied. In yet other embodiments,the determination of whether to create such a private excess capacitypool for a user may instead be performed at other times, such as uponreceiving a request from such a dedicated capacity user to use excesscomputing capacity resources. Furthermore, in at least some embodiments,the subscriber user may configure other aspects of such a private excesscomputing capacity pool for the user, such as how much of the dedicatedcapacity use is to be available as part of the private excess capacitypool (e.g., all, a specified percentage or specified number of computingnodes, etc.), to what users the private excess capacity pool is to beavailable, certain time periods and/or other criteria during which theprivate excess capacity pool is to be available or not available, etc.

If it is instead determined at block 612 that a request to subscribe foruse of dedicated program execution capacity is not received, the routineinstead continues to block 630, where the routine determines whether arequest is received to execute one or more programs on behalf of asubscriber user on allocated dedicated program execution capacity (e.g.,a current request for immediate execution, a previously scheduledrequest for execution, etc.), and that the corresponding dedicatedprogram execution capacity is not already in use or scheduled for usefor other dedicated program execution. If sufficient dedicated programexecution capacity is not available, an error message or other similarresponse is provided, such as with respect to block 635. In someembodiments, the routine may also ensure that the request for executionhas been received within an appropriate use period and/or may otherwiseauthorize the request (e.g., authenticate the request, authorize thesubscriber user, etc.). If an appropriate request is received for use ofdedicated capacity, the routine continues to block 640 to determine ifthe allocated dedicated program execution capacity to be used for therequest is currently in use as part of fulfilling a prior request fromthe requester as part of a private excess computing capacity pool forthe requester. If such current private excess computing capacity pooluse is identified in block 645, the routine continues to block 650, andotherwise continues to block 660 to perform the requested execution,such as by initiating the execution of the one or more programs on theallocated program execution capacity. If the routine first proceeds toblock 650 before block 660, the routine in block 650 initiates atransfer of the prior request from the private excess computing capacitypool to a general excess computing capacity pool, since the privateexcess computing capacity pool no longer has current availability tofulfill the prior request, although in other embodiments and situations(e.g., based on instructions specified for the prior request), theroutine may instead leave the prior request in a queue for the privateexcess computing capacity pool so that it is deferred until sufficientcapacity becomes available in the private excess computing capacitypool. In some embodiments, as part of block 660, the routine may selectcomputing resources and/or computing nodes on which to execute theprograms in various ways, and in some situations the routine mayterminate one or more programs of other users (e.g., general excesscapacity pool users) and/or otherwise free computing resources toperform the requested execution. In some embodiments, if a dedicatedcapacity user previously supplied some amount of her allocated dedicatedprogram execution capacity for use by one or more other users, such asto sell or lease that capacity to another user, then the dedicatedcapacity to fulfill the received request may not be available for use bythe dedicated user at the time of the request, unless the user is ableto reclaim the capacity for the request. In addition, in someembodiments, the current request from the subscriber user for the use ofthe dedicated capacity may be temporarily delayed, such as to allow aprior request from the subscriber user that is executing as part of aprivate excess capacity pool for the subscriber user to complete orotherwise perform one or more determined actions.

If it is instead determined at block 630 that a request to execute oneor more programs on behalf of a subscribing user on allocated programexecution capacity is not received, the routine continues to block 635to optionally perform one or more other indicated operations related todedicated capacity use as appropriate. For example, in some embodiments,such operations may include indicating some amount of dedicated programexecution capacity to make available as excess program executioncapacity, whether for a private excess capacity pool and/or a generalexcess capacity pool, and/or indicating that some amount of previouslyspecified program execution capacity is to be reclaimed for use by thededicated capacity user. In addition, as previously noted, the routinein block 635 may provide an error message or other related informationif the request received in block 605 is not fulfilled. In addition, insome embodiments, a request or instruction may be received in block 605to terminate previously initiated dedicated capacity use, and if so theroutine in block 635 may perform such program termination and alsoupdate the corresponding private excess computing capacity pool (if any)or general excess computing capacity pool of the resulting availableexcess capacity—in other embodiments, the user may instead terminate theexecution of the programs on the computing nodes without notifying theroutine 600, and the PESSM module may later automatically identify theresulting excess computing capacity (e.g., with respect to block 475 ofFIG. 4).

After blocks 618, 635 or 660, the routine continues to block 699 andreturns.

FIGS. 5A-5B are a flow diagram of an example embodiment of an ExcessCapacity Usage Manager routine 500. The routine may be provided by, forexample, execution of the Excess Capacity Usage Manager module 344 ofthe PESSM module 340 of FIG. 3, or as part of the PESSM modules 110 and180 of FIGS. 1A and 1B, respectively, and/or a PESSM module (not shown)that performs operations corresponding to FIGS. 2A and 2B, and may beinitiated from block 435 of routine 400 in FIG. 4 or otherwise invoked.

In the illustrated embodiment, upon invocation of the routine 500, arequest, information and/or other indication related to excess capacityuse is provided to the routine at block 502. At block 505, the routinethen determines whether an indication is received to add programexecution capacity to available excess program execution capacity, suchas based on information obtained with respect to block 475 of FIG. 4, oras triggered by the termination of use of dedicated computing capacitywith respect to block 635 of FIG. 6. If so, the routine continues toblock 510 to add the indicated program execution capacity to availableprogram execution capacity. In particular, if the excess programexecution capacity corresponds to a private excess computing capacitypool, then that private pool is selected to receive the indicated excesscapacity, and otherwise a general excess computing capacity pool isselected. In addition, in some embodiments requests to create newprivate excess capacity pools may be received and handled with respectto block 510, or instead with respect to block 595 as discussed below.For example, in some embodiments, the routine may add one or moreindications of such indicated program execution capacity (e.g., one ormore particular computing nodes, etc.) to the selected pool of availableprogram execution capacity. In some embodiments, multiple pools may beprovided, as previously discussed with respect to private and generalexcess capacity pools, and/or in other manners (e.g., various differenttypes of program execution capacity may be available and grouped intocorresponding private and/or general pools associated with the type ofprogram execution capacity).

If it is instead determined at block 505 that an indication to addexcess program execution capacity is not received, the routine continuesto block 515 to determine whether an indication is received to removeprogram execution capacity from the available excess program executioncapacity. If so, the routine continues to block 520 to select acorresponding private and/or general excess capacity pool from which theexcess capacity is to be removed (e.g., based on particular programexecution capacity that is indicated, such as for one or more programscurrently executing using excess capacity). The routine then removes theindicated program execution capacity from the available excess programexecution capacity for the selected capacity pool, such that theindicated program execution capacity (or an equivalent amount of programexecution capacity) is no longer available as excess program executioncapacity to execute programs on behalf of excess capacity users for theselected capacity pool.

If it is instead determined in block 515 that an indication to removeprogram execution capacity from available program execution capacity isnot received, the routine continues instead to block 525 to determinewhether a request to execute one or more programs on some amount ofavailable excess program execution capacity on behalf of an excesscapacity user is received (or a previously scheduled request for suchexecution has been triggered). If so, the routine continues to block 530to select a corresponding private and/or general excess capacity poolfrom which the excess capacity is to be obtained for executing one ormore programs for the request (e.g., based on the excess capacity user,or instead on another indication of particular program executioncapacity to use), and to optionally obtain or receive additionalinformation from a requesting excess capacity user related to requestedexecution. In some embodiments, such additional information may includeconfiguration information, such as indications of an amount and/or typeof program execution capacity requested (e.g., including minimum andmaximum amounts), a bid amount (e.g., including minimum and maximum bidamounts), an expiration time, a particular excess capacity pool to use(e.g., only a particular private excess capacity pool associated withthe user, or to use a particular private excess capacity pool ifavailable but to otherwise use a general excess capacity pool), etc. Insome embodiments, some or all such additional information may instead beincluded as part of the request received in block 502, or as part of aseparate configuration and/or registration performed by the excesscapacity user. In addition, in some embodiments, the routine may providefeedback to an excess capacity user of one or more types, such asindicating likely characteristics of the requested execution (e.g., alikely time that the request will be executed, a likely duration ofexecution, a likely excess capacity pool to be used, etc.) and/oroptional—other information (e.g., suggested configurations). After block530, the routine continues to block 535 to add the request to a group ofcurrent requests for execution on excess program execution capacity forthe selected excess capacity pool to be used. In other embodiments,rather than add the request to a group of other requests, the routinemay instead attempt to immediately satisfy the request, such as bydetermining whether there is available excess program execution capacityto execute the request at that immediate time (e.g., in a particularprivate excess capacity pool), and initiating execution of the programsif so, or taking other action if not (e.g., moving the request from theunavailable private excess capacity pool to a general excess capacitypool, failing, etc.).

If it is instead determined at block 525 that a request to executeprograms on available excess program execution capacity is not received,the routine continues to block 540 to determine whether a request toremove an indicated previous request for execution is received (e.g., aindicated request for execution that was previously added to a group ofrequests at block 535), such as a request from an excess capacity userto cancel a current request for execution and/or a received indicationthat the request has otherwise expired, etc. If so, the routinecontinues to block 545 to terminate any programs associated with theindicated request that are currently executing on some amount of excessprogram execution capacity, and then continues to block 550 to removethe indicated request from one or more groups of requests that includethe indicated request, such that the indicated request will notsubsequently be considered for execution on excess program executioncapacity.

After blocks 510, 520, 535 and 550, or if it was instead determined atblock 540 that a request to remove an indicated request for execution isnot received, the routine continues to block 555 to determine whether tomanage current requests for execution on excess program executioncapacity. For example, in some embodiments, indication received in block502 may have been passed into the routine 500 to manage the requestsand/or may have been provided based upon a change in the availableprogram execution capacity (e.g., by adding to or removing from theavailable program execution capacity in blocks 510 and 520,respectively), and/or a change in the current request for execution(e.g., by adding or removing requests in blocks 535 and 550,respectively), etc. If so, the routine continues to block 560 todetermine an amount of currently available excess program executioncapacity for one or more private and/or general excess computingcapacity pools in use, such as including an amount of program executioncapacity added and/or removed from the available program executioncapacity at blocks 510 and 520, respectively. After block 560, theroutine continues to block 562 to select pending requests that may beexecuted using any available private excess computing capacity pools(e.g., immediately executed or executed during an upcoming time intervalperiod), such as requests that are already being executed using aprivate excess capacity pool, requests that are queued for the privateexcess capacity pools, requests that are currently being executed usinga general excess capacity pool but that have a corresponding privateexcess capacity pool that is preferred if it is available, requests thatare currently being queued for a general excess capacity pool but thathave a corresponding private excess capacity pool that is preferred ifit is available, etc. For any such selected requests, the routine inblock 560 then allocates a corresponding amount of excess computingcapacity from the corresponding private excess computing capacity pool(or schedules such an allocation for an upcoming time interval period).The routine then continues to block 565 to, with respect to anyremaining requests that are not selected in block 562, select otherrequests to be executed using one or more general excess computingcapacity pools (e.g., immediately executed or executed during anupcoming time interval period), and allocate groups of the currentlyavailable excess program execution capacity from the correspondinggeneral excess computing capacity pool(s) for use by those selectedother requests.

As discussed in greater detail, the selection of requests in blocks 562and 565 may be performed in various manners in various embodiments,including based at least in part on priorities associated with therequests and their users. For example, in some embodiments, the routineattempts to allocate an amount of the excess program execution capacityfrom a corresponding excess computing capacity pool to each requestbased on its request (e.g., a number of computing nodes specified,etc.). In some such embodiments, if there is sufficient currentlyavailable excess program execution capacity to satisfy all the currentrequests for execution for a particular excess computing capacity pool,then each of the requests will be allocated a requested amount of thatexcess program execution capacity for executing programs associated withthe request. In cases where there is not sufficient currently availableexcess program execution capacity to satisfy all the current requestsfor a particular excess computing capacity pool, the routine prioritizesthe requests and attempts to satisfy higher priority requests prior tolower priority requests. In various embodiments, priority may be basedon one or more of a particular user associated with a private excesscomputing capacity pool, a bid amount, a time at which the request wasreceived, etc. In various embodiments, the routine may determine whichof the currently available excess program execution capacity to allocatefor use by the requests in various ways, such as described elsewhere.

After block 565, the routine continues to block 570 to terminate anyexecuting programs associated with a request that are already executingon excess program execution capacity but that were not selected forcurrent execution in blocks 562 and 565, such as to reflect that therequest has expired or was not sufficiently high priority to result incurrent ongoing satisfaction. In block 575, the routine then executesone or more programs associated with each of the requests (and/or leavespreviously executing programs on excess program execution capacity thatwas selected for ongoing execution in block 565). After block 575, theroutine continues to block 580 to optionally perform housekeepingoperations. For example, in some embodiments, the routine may detect andindicate if there are any requests for execution in the group ofrequests that are expired or otherwise should be removed, or movedbetween excess computing capacity pools.

If it is instead determined at block 555 not to manage current requestsfor execution on excess program execution capacity, the routinecontinues to block 595 to optionally perform one or more other indicatedoperations as appropriate. For example, the request received in block502 may be from a user to create a new private excess capacity pool forthe user (e.g., based on using some or all of some dedicated capacityallocated to the user), such as in a manner similar to that discussedwith respect to block 618 of FIG. 6, or to modify the configuration ofan existing private excess capacity pool—if so, the routine may performcorresponding actions in block 595. After blocks 580 or 595, the routinecontinues to block 599 and returns.

FIG. 7 is a flow diagram of an example embodiment of an On-DemandVariable Capacity Usage Manager routine 700. The routine may be providedby, for example, execution of the On-Demand Variable Capacity UsageManager module 346 of the PESSM module 340 of FIG. 3, or as part of thePESSM modules 110 and 180 of FIGS. 1A and 1B, respectively, and/or aPESSM module (not shown) that performs operations corresponding to FIGS.2A and 2B, and may be initiated from block 455 of routine 400 in FIG. 4,or otherwise invoked.

In the illustrated embodiment, the routine 700 begins at block 705,where a request, information and/or other indication related toon-demand variable capacity use is received. At block 710, the routinethen determines if the request is to execute one or more programs oncurrently available on-demand variable computing capacity (e.g., acurrent request for immediate execution, a previously scheduled request,etc.). As discussed elsewhere, such a request may specify various typesand/or amounts of program execution capacity on which to execute one ormore programs on behalf of a variable capacity user. If it is determinedin block 710 that a request to execute one or more programs is received,the routine continues to block 744. At blocks 744 and 746, the routinethen determines whether the requested program execution capacity iscurrently available. If so, the routine continues to block 748 toinitiate the execution of the one or more indicated programs on theavailable variable program execution capacity. If not, the routinecontinues to block 750, where the request for variable program executioncapacity fails, such as by not executing the requested one or moreprograms. In other embodiments, other actions may optionally be taken insuch situations, such as to query the user whether to move the requestto a queue for use with excess computing capacity, or to insteadautomatically perform such a move in at least some embodiments andsituations. In addition, in some embodiments, in response to a requestto execute programs on variable program execution capacity, the routinemay automatically terminate one or more programs of excess capacityusers to free variable program execution capacity, such as by sending acorresponding request to an Excess Capacity Usage Manager module.

If it is instead determined in block 710 that a request to execute oneor more programs is not received, the routine continues to block 790 toperform one or more other operations as appropriate. After blocks 748,750 or 790, the routine continues to block 799 and returns.

It will be appreciated that in some embodiments the functionalityprovided by the routines discussed above may be provided in alternativeways, such as being split among more routines or consolidated into fewerroutines. Similarly, in some embodiments illustrated routines mayprovide more or less functionality than is described, such as when otherillustrated routines instead lack or include such functionalityrespectively, or when the amount of functionality that is provided isaltered. In addition, while various operations may be illustrated asbeing performed in a particular manner (e.g., in serial or in parallel)and/or in a particular order, those skilled in the art will appreciatethat in other embodiments the operations may be performed in otherorders and in other manners. Those skilled in the art will alsoappreciate that the data structures discussed above may be structured indifferent manners, such as by having a single data structure split intomultiple data structures or by having multiple data structuresconsolidated into a single data structure. Similarly, in someembodiments illustrated data structures may store more or lessinformation than is described, such as when other illustrated datastructures instead lack or include such information respectively, orwhen the amount or types of information that is stored is altered.

From the foregoing it will be appreciated that, although specificembodiments have been described herein for purposes of illustration,various modifications may be made without deviating from the spirit andscope of the invention. Accordingly, the invention is not limited exceptas by the appended claims and the elements recited therein. In addition,while certain aspects of the invention are presented below in certainclaim forms, the inventors contemplate the various aspects of theinvention in any available claim form. For example, while only someaspects of the invention may currently be recited as being embodied in acomputer-readable medium, other aspects may likewise be so embodied.

1. A computer-implemented method for managing execution of programs forusers, the method comprising: reserving multiple computing nodes for useby a first user to enable the first user to receive guaranteedavailability of dedicated access to the reserved computing nodes forexecuting programs during a specified period of time, the reservedcomputing nodes being a subset of a plurality of computing nodesprovided by a program execution service that are each configurable toexecute one or more programs for one of multiple users of the programexecution service; automatically determining to use each of the reservedcomputing nodes as part of a private excess computing capacity pool forthe first user during the specified period of time while that reservedcomputing node is not in use providing dedicated access to the firstuser, the automatic determining being performed by one or moreprogrammed computing systems of the program execution service andwithout knowledge of the first user; executing one or more firstprograms for the first user during a first time period subset of thespecified period of time using the reserved computing nodes, theexecuting of the one or more first programs being in response to a firstrequest to use the dedicated access of the first user to the reservedcomputing nodes; receiving a second request from the first user toperform execution of one or more second programs on an indicatedquantity of computing nodes for the first user during a second timeperiod subset of the specified period of time that is distinct from thefirst time period subset, the second request being to obtain theindicated quantity of computing nodes from a general excess computingcapacity pool of the program execution service that is based on unusedexcess computing nodes of the program execution service to which thefirst user does not have dedicated access, use of the general excesscomputing capacity pool being provided without guaranteed availabilityof continuing use of those unused excess computing nodes; automaticallydetermining to use the private excess computing capacity pool for thefirst user for at least some of the execution of the one or more secondprograms on the indicated quantity of computing nodes for the secondrequest during the second time period subset in lieu of using thegeneral excess computing capacity pool, the automatic determining to usethe private excess computing capacity pool being performed by the one ormore programmed computing systems of the program execution service; andinitiating the at least some execution of the one or more secondprograms for the first user during the second time period subset byusing one or more of the reserved computing nodes as part of the privateexcess computing capacity pool.
 2. The method of claim 1 wherein theprogram execution service is a fee-based service, wherein the first userpays a first incremental fee for using one of the reserved computingnodes for a designated time interval as part of the dedicated access ofthe first user, wherein the first user pays a second fee for using oneof the unused excess computing nodes of the general excess computingcapacity pool for the designated time interval, the first fee beinglower than the second fee, and wherein the automatic determining to usethe private excess computing capacity pool for the first user for the atleast some execution of the one or more second programs is based atleast in part on the first user being charged the lower first fee forusing the reserved computing nodes as part of the private excesscomputing capacity pool.
 3. The method of claim 2 wherein the privateexcess computing capacity pool includes a quantity of the reservedcomputing nodes at a time of the automatic determining to use theprivate excess computing capacity pool that is less than the indicatedquantity of computing nodes, wherein the initiating of the at least someexecution of the one or more second programs by using the one or morereserved computing nodes as part of the private excess computingcapacity pool includes using the included quantity of the reservedcomputing nodes, and wherein the method further comprises initiatingother execution of the one or more second programs for the first userduring the second time period subset by using one or more of the unusedexcess computing nodes as part of the general excess computing capacitypool, the one or more unused excess computing nodes being of a quantitythat is a numerical difference between the indicated quantity ofcomputing nodes and the included quantity of the reserved computingnodes.
 4. A computer-implemented method for managing execution ofprograms for users, the method comprising: reserving program executioncapacity of one or more computing nodes for a first user during aspecified period of time to enable the first user to receive dedicatedaccess to execute programs using the reserved program execution capacityduring the specified period of time, the reserved program executioncapacity being a subset of available program execution capacity providedby a plurality of computing nodes of a program execution service, theplurality of computing nodes each being configurable to execute one ormore programs; executing one or more first programs for the first userduring a first time period subset of the specified period of time usingthe reserved program execution capacity, the executing of the one ormore first programs being in response to a first request to use thededicated access of the first user to the reserved program executioncapacity; receiving a second request from the first user to execute oneor more second programs for the first user during a second time periodsubset of the specified period of time that is distinct from the firsttime period subset, the second request being to execute the one or moresecond programs using unused excess capacity of the available programexecution capacity of the program execution service to which the firstuser does not have dedicated access, use of the excess capacity of theprogram execution service having first program execution characteristicscontrolled by the program execution service that differ from secondprogram execution characteristics controlled by the program executionservice that occur from use of the reserved program execution capacity;automatically determining to use the reserved program execution capacityfor the first user to execute the one or more second programs for thesecond request during the second time period subset, the automaticdetermining to use the reserved program execution capacity beingperformed by one or more programmed computing systems of the programexecution service and being based at least in part on the first user nototherwise using the dedicated access to the reserved program executioncapacity during the second time period subset; and initiating executionof the one or more second programs for the first user during the secondtime period subset by using the reserved program execution capacity, theexecution of the one or more second programs having at least some of thesecond program execution characteristics based on the using of thereserved program execution capacity.
 5. The method of claim 4 furthercomprising: receiving a third request from the first user to execute oneor more third programs for the first user during a third time periodsubset of the specified period of time, the third request being toexecute the one or more third programs using the unused excess capacityof the program execution service; automatically determining to not usethe reserved program execution capacity for the first user to executethe one or more third programs for the third request during the thirdtime period subset, the automatic determining to not use the reservedprogram execution capacity being based at least in part on the reservedprogram execution capacity being otherwise used by the first user duringthe third time period subset; and attempting to initiate execution ofthe one or more third programs for the first user during the third timeperiod subset by using the unused excess capacity of the programexecution service.
 6. The method of claim 5 wherein the execution of theone or more third programs using the unused excess capacity has thefirst program execution characteristics, the first program executioncharacteristics including a first fee that is charged to the first userfor a first specified amount of program execution capacity, and whereinthe method further comprises, after the execution of the one or morethird programs has been initiated using the unused excess capacity ofthe program execution service and before the execution of the one ormore third programs has completed: automatically determining that atleast some of the reserved program execution capacity for the first userhas become available; automatically determining to modify continuingexecution of the one or more third programs to use the at least someavailable reserved program execution capacity; and initiating thecontinuing execution of the one or more third programs using the atleast some available reserved program execution capacity in lieu of theexcess capacity of the program execution service, the continuingexecution of the one or more third programs having the at least somesecond program execution characteristics, the at least some secondprogram execution characteristics including a second fee that is chargedto the first user for a second specified amount of program executioncapacity, the second fee being distinct from the first fee.
 7. Themethod of claim 4 further comprising: receiving a third request from asecond user to execute one or more third programs for the second userduring a third time period subset of the specified period of time, thethird request being to execute the one or more third programs using theunused excess capacity of the program execution service, the second userbeing distinct from the first user; automatically determining to not usethe reserved program execution capacity for the first user to executethe one or more third programs for the third request during the thirdtime period subset, the automatic determining to not use the reservedprogram execution capacity being based at least in part on the seconduser being distinct from the first user and being despite the reservedprogram execution capacity not being otherwise used by the first userduring the third time period subset; and attempting to initiateexecution of the one or more third programs for the second user duringthe third time period subset by using the unused excess capacity of theprogram execution service.
 8. The method of claim 4 wherein the secondrequest from the first user to execute the one or more second programsfor the first user includes an indication of a quantity of multiplecomputing nodes to use, wherein the reserved program execution capacityfor the first user that is not otherwise being used by the first userduring the second time period subset corresponds to an availablequantity of the one or more computing nodes that is less than theindicated quantity, wherein the initiating of the execution of the oneor more second programs for the first user by using the reserved programexecution capacity includes using the available quantity of the one ormore computing nodes, and wherein the method further comprisesinitiating other execution of the one or more second programs for thefirst user during the second time period subset by using the unusedexcess capacity of the program execution service, the initiating of theother execution including using one or more unused excess computingnodes of a quantity that is a numerical difference between the indicatedquantity and the available quantity.
 9. The method of claim 4 furthercomprising automatically determining to use the reserved programexecution capacity as part of a private excess computing capacity poolfor the first user during the specified period of time while thatreserved program execution capacity is not in use providing dedicatedaccess to the first user, and automatically monitoring use of thereserved program execution capacity for the first user to determineavailability of the reserved program execution capacity for the privateexcess computing capacity pool.
 10. The method of claim 9 wherein theautomatic determining to use the reserved program execution capacity aspart of the private excess computing capacity pool for the first user isperformed without knowledge of the first user.
 11. The method of claim 4wherein the automatic determining to use the reserved program executioncapacity for the first user to execute the one or more second programsfor the second request during the second time period subset includesdetermining to use the reserved program execution capacity in lieu ofthe unused excess capacity of the program execution service, theautomatic determining to use the reserved program execution capacity aspart of the private excess computing capacity pool for the first user toexecute the one or more second programs for the second request beingperformed without knowledge of the first user.
 12. The method of claim 4wherein the second program execution characteristics from use of thereserved program execution capacity includes guaranteed availability ofthe reserved program execution capacity for the first user, and whereinthe first program execution characteristics for use of the excesscapacity of the program execution service includes a lack of guaranteeof continuing availability of the excess capacity.
 13. The method ofclaim 4 wherein the second program execution characteristics from use ofthe reserved program execution capacity includes a first ongoing feecharged to the first user for use of a specified amount of the reservedprogram execution capacity for a specified time interval, wherein thefirst program execution characteristics for use of the excess capacityof the program execution service includes a second fee charged to thefirst user for use of the specified amount of the excess capacity forthe specified time interval, the first fee being less than the secondfee, wherein the automatic determining to use the reserved programexecution capacity for the first user for executing the one or moresecond programs is based at least in part on the first user beingcharged the lower first fee for using the reserved program executioncapacity for that executing of the one or more second programs, andwherein the at least some second program execution characteristics forthe execution of the one or more second programs includes use of thelower first fee.
 14. The method of claim 4 wherein the reserved programexecution capacity is based on use of multiple reserved computing nodesfor the first user, wherein all of the multiple reserved computing nodesare designated by the first user to be used in lieu of the unused excesscapacity of the program execution service during portions of thespecified time period other than the first time period subset, whereinthe initiating of the execution of the one or more second programs forthe first user by using the reserved program execution capacity includesusing a subset of the multiple reserved computing nodes, and wherein themethod further comprises initiating execution of one or more other thirdprograms on behalf of the first user during one or more portions of thespecified time period by using at least some of the multiple reservedcomputing nodes.
 15. The method of claim 4 further comprising, duringthe execution of the one or more second programs using the reservedprogram execution capacity: receiving a third request from the firstuser to use the dedicated access of the first user to the reservedprogram execution capacity to execute one or more third programs for thefirst user; determining to terminate the execution of the one or moresecond programs using the reserved program execution capacity based onthe received third request; and initiating execution of the one or morethird programs for the first user by using the reserved programexecution capacity in lieu of the execution of the one or more secondprograms.
 16. The method of claim 4 further comprising, during theexecution of the one or more second programs using the reserved programexecution capacity: receiving a third request from the first user to usethe dedicated access of the first user to the reserved program executioncapacity to execute one or more third programs for the first user; andin response to the received third request, automatically determining tomodify continuing execution of the one or more second programs to usethe excess capacity of the program execution service, and initiating thecontinuing execution of the one or more second programs using the excesscapacity in lieu of the reserved program execution capacity, thecontinuing execution of the one or more second programs having the firstprogram execution characteristics.
 17. The method of claim 16 whereinthe at least some second program execution characteristics for theexecution of the one or more second programs using the reserved programexecution capacity includes a first fee that is charged to the firstuser for a first specified amount of program execution capacity, andwherein the first program execution characteristics for the continuingexecution of the one or more second programs using the excess capacityincludes a second fee that is charged to the first user for a secondspecified amount of program execution capacity, the second fee beingdistinct from the first fee.
 18. The method of claim 4 wherein theplurality of computing nodes include, for each of multiple physicalcomputing systems, multiple virtual machines hosted by the physicalcomputing system that are each configurable to execute at least oneprogram, and wherein the one or more computing nodes used for thereserved program execution capacity are each hosted virtual machines.19. A computer-readable storage medium whose contents enable a computingsystem to perform a method comprising: providing one or more reservedcomputing-related resources to which a first user has dedicated accessfor use during program execution for a specified period of time, thereserved computing-related resources being managed by anetwork-accessible service remote from the first user and not being usedfor dedicated access by the first user during an indicated portion ofthe specified period of time; automatically responding to a request fromthe first user to use at least one indicated computing-related resourceduring execution of one or more first programs for the first user duringthe indicated portion, the at least one computing-related resource beingindicated to be unused excess computing-related resources of the remoteservice to which the first user does not have dedicated access, theautomatic responding including: determining that the reservedcomputing-related resources for the first user include the at least oneindicated computing-related resource, and determining to use thereserved computing-related resources during the execution of the one ormore first programs for the first user during the indicated portion inlieu of the unused excess computing-related resources of the remoteservice; and initiating use of the reserved computing-related resourcesduring the execution of the one or more first programs for the firstuser during the indicated portion.
 20. The computer-readable storagemedium of claim 19 wherein the service is a program execution servicethat provides a plurality of computing nodes configurable to executeprograms of users of the program execution service, wherein the one ormore reserved computing-related resources include one or more of theplurality of computing nodes that are allocated for use by the firstuser in executing one or more programs, wherein the at least oneindicated computing-related resource is a specified quantity of one ormore of the plurality of computing nodes, and wherein the initiating ofthe use of the reserved computing-related resources during the executionof the one or more first programs includes initiating execution of theone or more first programs by at least the specified quantity ofcomputing nodes from the one or more computing nodes allocated for useby the first user.
 21. The computer-readable storage medium of claim 20wherein the providing of the one or more reserved computing-relatedresources to which the first user has dedicated access includesexecuting one or more second programs for the first user for a secondportion of the specified period of time using the dedicated access ofthe first user, the second portion being distinct from the indicatedportion, and wherein the execution of the one or more first programs forthe first user by the at least specified quantity of computing nodes hasfirst program execution characteristics that differ from second programexecution characteristics occurring from use of the unused excesscomputing-related resources of the remote service.
 22. Thecomputer-readable storage medium of claim 19 wherein the request fromthe first user to use at least one indicated computing-related resourceincludes an indication of a type of computing-related resource, andwherein the at least one indicated computing-related resource is adetermined amount of the indicated type.
 23. The computer-readablestorage medium of claim 19 wherein the at least one indicatedcomputing-related resource is at least one of persistent storage,memory, and processor cycles.
 24. The computer-readable storage mediumof claim 19 wherein the computer-readable medium is a memory of thecomputing system that stores the contents, and wherein the contents areinstructions that when executed program the computing system to performthe method.
 25. A computing system configured to manage execution ofprograms for users, comprising: one or more processors; and a systemmanager module that is configured to, when executed by at least one ofthe one or more processors, manage execution of programs for users of aprogram execution service by, for each of multiple of the users:providing a specified first amount of reserved program executioncapacity to which the user has dedicated access for executing programs,the reserved program execution capacity being a subset of programexecution capacity provided by the program execution service; and afterthe providing of the specified first amount of reserved programexecution capacity, automatically responding to a request from the userto execute one or more first programs for the user using a second amountof excess program execution capacity of the program execution service towhich the user does not have dedicated access, the automatic respondingincluding: automatically determining whether the reserved programexecution capacity for the user includes available program executioncapacity of at least the second amount that is not in use by the user;if the reserved program execution capacity for the user is automaticallydetermined to include the available program execution capacity of atleast the second amount, initiating execution of the one or more firstprograms for the user using the reserved program execution capacity forthe user; and if the reserved program execution capacity for the user isautomatically determined to not include the available program executioncapacity of at least the second amount, attempting to initiate executionof the one or more first programs for the user by obtaining use of otherexcess program execution capacity of the program execution service thatis currently unused, the other excess program execution capacity of theprogram execution service being distinct from the reserved programexecution capacity for the user.
 26. The computing system of claim 25wherein the program execution service uses a plurality of computingnodes to provide the program execution capacity for the programexecution service, the plurality of computing nodes each beingconfigurable to execute one or more programs for one or more of theusers of the program execution service, wherein the providing of thespecified first amount of reserved program execution capacity for one ofthe multiple users includes allocating one or more of the plurality ofcomputing nodes for dedicated use by the one user for a specified periodof time and includes executing one or more second programs for the oneuser for a portion of the specified period of time using the dedicatedaccess of the one user to the reserved program execution capacity of theallocated one or more computing nodes, and wherein the reserved programexecution capacity for the one user is automatically determined to notinclude the available program execution capacity of at least the secondamount if the automatic determining occurs during the portion of thespecified period of time when the dedicated access of the one user tothe reserved program execution capacity of the allocated one or morecomputing nodes is used for the executing of the one or more secondprograms.
 27. The computing system of claim 26 wherein the automaticdetermining of whether the reserved program execution capacity for theone user includes available program execution capacity of at least thesecond amount includes determining that the reserved program executioncapacity for the one user does include the available program executioncapacity of at least the second amount, and wherein the execution of theone or more first programs for the one user using the reserved programexecution capacity for the one user has first program executioncharacteristics that differ from second program executioncharacteristics occurring from use of the other excess program executioncapacity of the program execution service.
 28. The computing system ofclaim 25 wherein the system manager module includes softwareinstructions for execution by the one or more processors of thecomputing system.
 29. The computing system of claim 25 wherein thesystem manager module consists of a means for managing execution ofprograms for users of a program execution service by, for each ofmultiple of the users: providing a specified first amount of reservedprogram execution capacity to which the user has dedicated access forexecuting programs, the reserved program execution capacity being asubset of program execution capacity provided by the program executionservice; and after the providing of the specified first amount ofreserved program execution capacity, automatically responding to arequest from the user to execute one or more first programs for the userusing a second amount of excess program execution capacity of theprogram execution service to which the user does not have dedicatedaccess, the automatic responding including: automatically determiningwhether the reserved program execution capacity for the user includesavailable program execution capacity of at least the second amount thatis not is use by the user; and if the reserved program executioncapacity for the user is automatically determined to include theavailable program execution capacity of at least the second amount,initiating execution of the one or more first programs for the userusing the reserved program execution capacity for the user; and if thereserved program execution capacity for the user is automaticallydetermined to not include the available program execution capacity of atleast the second amount, attempting to initiate execution of the one ormore first programs for the user by obtaining use of other excessprogram execution capacity of the program execution service that iscurrently unused, the other excess program execution capacity of theprogram execution service being distinct from the reserved programexecution capacity for the user.